it doesnt work that way, maybe in theory but in pratice if you check the stats over the next patch you'll notice that low elo gold per game significaly dropped. Plus another bad side of it is denying entire waves of creep if its not a canon waves feels useless if the enemy some how manage to get the canon.
Another interesting fact to consider is some champs just have terrible attack speed, attack animation and base ad. Lissandra and Anivia comes to mind per say. They remove the extra 5 damage from minions, even when all that was in place pro players like Froggen would still miss canons on stage. Not counting all the canon minion SRO missed during is numerous games, it became a meme. My point is even pro's or ''higher'' elo do miss canon minion with out being denied the acces to it.
My point is simply, the game feels terrible, and the feeling might even be worst if you play a game of one for all since gold, exp are going faster.
Also, I think it was Meddler, said that they don't bring URF more to the server cause the player base drop after urf is released.
Maybe cause the game feels so slow after it, so instead of fastening the pace of league to adress the issue of the game feels slow compare to URF, they just dont release URF to prevent the feeling at all...
Its like saying i don't allow my self to eat sushi cause my KraftDiner taste like trash after. Why don't I try eating other stuff not as trash as KD in the first place.