Late game focused metas are much better for variety and gameplay than early game focused metas

When the meta revolves around early game, it typically revolves around who can get an early lead the fastest, and then who can snowball the game into an easy victory. This feels really bad for one side, because one mistake made by someone across the map can cost you the whole game. This also drowns out variety, because late game champions simply cannot reach their win condition when everyone picks early game champions. Games feel super snowbally, where even though you tried your best, you still feel like there was nothing you could do to turn around the play short of the enemy fucking up massively or you making a massive play.

When the meta revolves around late game however, things are different. Players can still get an early lead in this meta, since early game champions are still going to be more powerful than late game champions in these metas. But an early snowball doesn't mean the end of the game. Players can come back from dire situations easier than before because of how late game champions work. But this doesn't mean that early game champions are completely ruled out.

When there is a early game meta, the game usually ends before 25-30 minutes, or when late game champions begin to reach their win condition. Early game always happens no matter what, while games rarely reach late game unless there ended up being a stalemate. When there is a late game meta, the early game still happens, so early game champions can still be viable. They may not be meta, but they can be played. Late game champions have their win condition as a feasible goal, as well as early game champions having the ability to seize the victory.

Example: In an early game meta, gets to constantly gank and invade the poor 's jungle. snowballs the game super hard, and had no way to reach her win condition unless the played really poorly or had a massive fuckup.

In a late game meta, has to be more careful with his ganks and invades, but he can still do them and get an upper hand on , and possibly snowball the game. But since the pace of the game is slower, has a chance to farm up and be useful, outscaling and reaching her win condition.

TL;DR: In an early game meta, late game champions have no chance of getting strong unless the early game champions fuck up. In a late game meta, early game champions still get to have their moment of power and can make an impact, but late game champions still get a chance to reach their maximum potential.