Guinsoo gold cost increased, again. A lot of items nerfed/buffed and more new items

Well okay, riot nerfs guinsoo and his gold cost, and some patches later, they increase his gold cost, 2 times, from 3100 to 3300, and 3300 to 3500, so it's a worse ítem, with worse stats, with the same gold cost as before.

Can Someone explain why is this ítem getting nerfs over and over again, for so many patches?? Why can't they just let the ítem just how It is? Im the only one who's tired of playing a Game, wich is all the time changing and changing? What if i want to leave 1 month? Do I have to start from zero again? What will lol be in one month if they keep like this? Unnecesary changes all the time, while all the players are complaining about a few things, and riot is not listening? Im scared AF about the new items and some champs like rengar with the spear of shoujin, because It scales with AD, and jhin? O-m-g. Jhin can get over 900 AD, how much dmg will he cancel with this ítem with the guinsoo? How much dmg will deal some tanks (That actually deals a stupid ton of dmg) Like mundo, chogath?

Someone please explain me this changes, im trying to unserstand.