Why aren't people abusing spellbook better?

I have figured out some good builds for specific champs because of the jungle items. a simple smite/flash start and you have that option for a variety of situational items (but usually a specific item based on the champ). im gunna share my favourite ones with you scrubs, so you get the idea of why I do the things I do.

top lane tryn. smite/flash, spellbook and sorcery with all the cdr, stopwatch and future market. use the smite early on to keep early rage up, or try and double smite with your jungler to steal a worked on blue or red (its hilarious when it works, because you're like, "ok ima smite at 1k health ish, you smite after" and the double smite happens and their jungler is like WHAAAA. anyways, i digress.

-i start spell thief and 3 pots. start e, rush to river to try and get a free auto and e proc for a bit of extra gold early on. your first back swap to ignite, grab cull and a tome. maybe a pink ward. rush proto, then green runic echo. these 2 and a 1/2 ap items make your q's heal rather decent, and if you're maxing e you got decent wave clear. if its a poke lane or you're losing, 2 points in q. its all you really need for a while. after the two ap items, you rush the cdr of triforce (since you need cdr for more e and r). you should be done cull by then easily, so get your triforce, work on phantom dancer, ie, rageblade. no boots, you don't need them. if you're being kited, swap to ghost instead of ignite. save the spell thief as a last sell.

top lane nasus against a fat bully. smite/flash, spellbook with overgrowth. cdr, boots, stopwatch. try not to smite, but smite if you must to get those minions you couldnt auto in time. like if there is two minions taking wave agro, try and have smite ready to catch one of em.

-coin, 3 pots. first back buy cull, or defense of that lane. after, you're working on sheen, then more tankyness. all you need is sheen for the most part, work on countering that lanes damage. stax does not matter much in this build. after you have 1 defense item, your sheen, and maybe finished boots, work on either green cinderhulk to be tankier, or work on blood razor. you're most likely like "what, attack speed nasus, thats dumb!". shut the fuck up you schrodinger's brain complex victim. allow me to make a point here... if you manage to get your core of cdr and defense like glacial shroud, spirit visage, sheen, and blood razor, you can duo baron no problem. late game, if you have all your cdr = to 45% + blade of the ruined king+ blood razor, you can solo baron and it wont matter how many stax you have. attack speed also helps with the cdr of q, so when you ult you'll get an extra 2 or 3 q's off compared to just flat out tank. the sustain from bork also gives you general tankyness during combat and helps you get onto the adc with actives. lategame, i would have triforce, mercs, spirit visage, rg, bork, blo raz. again, stax wont matter at all with this build. if blood razor isn't doing it for ya, change it to cinder hulk (since you have over growth you'll jump a good size of hp). save the coin for last sell.

Support Chogath. smite/flash, spellbook with overgrowth and front line. this is a scaling lane, very passive unless you know you're good with landing q/start q. level 2, e surprisingly, for the dps and the potential to do dragon with your jungler if you can sneak off from the lane properly. again, level 2, you can do dragon with your jungler. after 6, ks everything you can with r, try and get dragons with it too. dont rush the standard 6 stax, focus on scaling with the "special" stax.

-first buy, targons and pots. first back, upgrade it or get boots, swap to heal tbh (unless you didn't get dragon yet)((i prefer heal because if you last long enough in the lane heal is an offense and defensive move to either survive, or get that stack early on in lane with r)). max w, then e. you're rushing your support item, green cinder hulk, and/or locket. by 20 you should have them, and a couple stax in r that were NOT the base 6 ones (if you don't suck)((remember, ksing with r is for the best for the TEAM, so you can scale locket and cinderhulk, and eventually titanic hydra)). lategame, you should have support item finished, green cinderhulk, locket, triforce (because it helps with cdr, sticking on people, movement speed, and when you get down to the brass tax of things, after your combo you're just an auto attacker), titanic hydra (because you were a good support and "secured" as many r stax as you possibly could, enjoy your 600+ damage active item). full combo, you hit w, then q, e , titanic, auto, r. ANY squishy is dead, anyone who didn't build tank stats is dead. mid game, you should be as scary as a 2nd top laner.

shaco mid, smite/flash, spellbook with sorcery, all cdr, stop watch and boots.

-rush proto, green runic, dusk blade, zonyas, ga (if their team is mostly squishy and so is yours) never get sheen since it gives you away from the clone. rush tiamat, green runic, static shiv, sunfire, abyssal (for fighting a tankier team and you wanna do mixed damage while being aoe) either build, start boxes, q, e, w, w, r, q, w, q, w, finish q off, leave e for last. e doesn't do all that much when you level it up so thats why you get green runic to give it the feel of some damage.

adc kog/vayne, twitch. smite/flash, spellbook with w/e. i myself like surviving more often, so i would go either overgrowth, or triumph. you might be "like, ew, overgrowth on adc? thats stupid"... well no, lategame you should have a decent amount of farm, 20 minutes you SHOULD have at least 50 extra hp because of overgrowth without buying ANY health items yet. if you do get some health items, buy a frozen mallet, and a phage ( don't need to upgrade the phage at all, just have it to work on the kite and hp of it with frozen mallet) this setup is to get blood razor, and bork. with this, you could technically go hurricane on VAYNE as well and not feel like an asshat for it. so 30 minutes in, you should have green blood razor, bork, hurricane, boots, working on your frozen mallet, and triforce or black cleaver (but if you didn't wanna upgrade the phage, i just prefer cdr myself so you can do more things in fights), you do you tho.

ekko mid/top/jungle. spellbook, with overgrowth and frontline

you're either going for green runic, or green cinder (yes, tank ekko still kinda works a bit, even if you're mid, a cinderhulk will help you live. rush sheen(gaunlet eventually even if you're ap for less likelyhood of you dying to towers/adcs while being able to slow the anyone to death), jungle item, abyssal/roa, void/liandries, spirit/zonyas.

green jungle items are, in my opinion, a wriggles lantern. use it. its not troll to have 2 extra wards and make objectives like dragons and baron easier. being able to solo dragons at any point or duo barons is what makes this all have viability. gj if you made it this far, I know these builds work, they are slower than rushing damage sure but the utility of them can win you games or at least feel like you're contributing to the team.