Subs are for marketing purpose partnered with twitch to promote champ paris. It is good for introducing new people into esport scene, not the game. Substainable esports scene needs revenue from sponsorship of events and not from purchases in the game, which is why riot is trying to bring viewers into the scene.
Not defending riot here, t2/3 should have more prize pool, but it is also fact that VCL don't have enough attention and viewership, and never will. T2/3 are for talent searching, no one wants to watch less skilled players, it's not entertaining, same with traditional sports, F2, G league, ... they are all not profitable. In a business perspective, why not try to build a stable viewership on t1 first rather than pour money into t2 that won't affect anything? If you think players need support, you are right, but the scene isn't big enough for t2/3, even t1 orgs are struggling, it's the whole esports scene, not just valorant, don't be delusional and think riot can solve this. Also, consider open circuit events for teams to compete for master/champs spot with t1 teams. This will attract lots of investment and lots of opportunity for the players. This is how to support t2/3, not just pouring more money into it. Lots of people on twitter thinks that increasing prize money will do anything, which I think is just stupid. Not to offend anyone, if your team is terrible you aren't suppose to make much money, G leaguers don't make nba money.