Small creators ads
Small creators have little to no opportunity to gain from ads because there simply aren't the viewers to gain anything monetarily.
A fix would be to provide a greater incentive (more ad free time/bits but also the ability to opt out entirely unless the view count crosses a certain threshold e.g. 100+ viewers.
Ads may be what keeps twitch free but there are plenty of 24 hour streams that constantly run on twitch because people come to twitch for the non-TV experience. Twitch threatens itself by changing into a cable-like experience