Well I agree that players in these leagues should have to make a multi-season commitment, but I think that commitment can just be somewhat discounted rather than slashed to be 1/3 of the current price. Maybe the season sims 5 games per day instead of 3 (so that it doesn't sim twice during sleep hours, which I think most people would agree they wouldn't want). Let's assume this only applies to games; there are still 6 daily cycles just like there are now, and offseason stuff goes at the same pace (so that, for example, you still have a full day to do budgets, 3 days to do FAs, etc. which I think most would want to preserve).
With this model, a season (which currently lasts ~87 days) would have an 8-day offseason, 3 and 2/3-day spring training, a 1 and 2/3-day "prepare for regular season" (which we have right now, and could easily be trimmed to 1 day), a ~35-day regular season, and a ~7-day playoffs. So we'd trim the season down from ~87 days to ~55 days, which is 63.2% of a current season.
Let's say WiS charges $16 per season for a turbo league, which is 64% of a regular season. WiS makes a tiny extra profit from these leagues, secures 3-year commitments from the players, and gives players a new option that allows them to play in these faster leagues. This would allow leagues to still have 32 teams with little turnover, and it seems like everyone gets what they want. Why not do it this way?