I wish Riot would make every champ viable in esports

each of those champs has seen play at some point, as have most champs on the roster. The issue is that as the meta shifts, certain champs scale with certain items and it effectively eliminates 90 champions from viability because they don't work as well with the current items and balance state of the game.

It's more than simply item scaling, it's what a champion does for a composition. If you are playing a sieging comp, it doesn't matter if you do insane damage to champions. It maters if you can put damage on towers at range. If you're a pick comp, you need to be able to run tp as a solo laner and you probably want some kind of wave clear on your adc and reliable cc on your support.

Once you determine these necessities, there are a very few champions who are optimal at what you need them to do in your composition and if you want to win at any cost, you learn to play those optimal champions. It's not a matter of "ballance" at all. It is impossible for all champions to be equally strong at all things and still be unique.

For all that people bitch about balance in this game, you clearly have no fucking idea what TRUE imbalance is. League isn't perfect, but it's better than any game of it's type has ever been with a much bigger roster than is reasonable for that to be so.