Most reader don't even understand the reason patreon is better than SS for the readers. They only see "15 chapters in advance for 50$".
In reality those preview chapters were just a bonus. The real benefit was the CROWDfounding to get the release rate faster for everyone. Regular supporter, one-time supporter and leecher. 1$ Of 1000 people can get 4-5 chapter more per week than the regular release. Well... except the old translator of Swallowed Star, he didn't really up the chapters after some point. His last goal was at 1k, even though he was at 2.6k+. (beginning of the month. At the end of the month over 4k - but they didnt pay up.)
QI would earn about 200$ per chapter, if only 1000 people read them. And no matter how many people buy the chapters, it won't increase the release rate.
Readers overall would have paid more money after 5 chapters, than if 1k get donated by patreon. Obviously QI wouldn't get as much money (or any at all? idk) from Patreon supporters... On the other side translators get waaaaaaay less from Spirit Stones.
Basically everyone losses out, except QI. Readers lose out. Translators loses out.