Roblox pushes games that statistically are doing really well. and I am fairly certain unoptimized games that are “a laggy mess” won’t be pulling in remotely enough players to qualify for that. There is zero excuse here regarding how it will negatively impact the quality of popular games because most “low quality games” you are probably referring to are aiming to run on toasters, not top-end hardware.
Roblox recently began retaining images in their original resolutions, clearly they don’t see storage as an issue and their focus is more on how best to implement it into the engine.