Now, for the rest of it: most vtubers actually fulfil their donothon goals, those that don't usually offer refunds so they can't be sued for fraud (see Pochi's graduation notice), a person getting sick can fulfil their goals later (and donothon goals usually take months to fulfil anyway) and the fact that Idol corp decided that donothon money would go straight to talents without being subject to the talent/agency split seems more of a problem for Idol Corp than for the concept of donothons or donating to them.
Just to have it here in one place and to show it's mostly a Pochi problem not idol:
Juna set very simple goals, most of which she finished during donothon itself. And the only one marked unfinished is a cover of chat's choice
Yuko has things left that require getting in touch with a publisher or waiting on a lot of people other than her. She will probably not finish lewd ASMR with the way things are currently going
Fuyo also has things left that require a lot of commissions and waiting on a lot of people
Rin has fanart left and she also did most of the goals during a stream itself like Juna
Coni has the usual suspects of unfinished covers and things that require irl engagement
Kai is the same with covers and fanart
Momo is covers, fanart, vlog and "chosing outfit for school" whatever that is
Poko has a lot unfinished but it was in November and... you guessed it, it's mostly covers and fanart
Now, Roca did fuckall, but she also did it at the very end of December and is probably feeling her ass being lit on fire right now
Notice how all of them only did one donothon, with generally easily achievable goals, and most of them, including the 2nd gen who did theirs half a year later, are all finished when it comes to things they could've done themselves
Pochi promised a lot of things that are very time and money consuming, did two donothons, didn't deliver on this goals, and one of her goals was "Pochi & other Idol girls Future Off Collab Escape Room/Funhouse Vlog". So basically everyone else has to do things so she could get the money from it. The fact that she was allowed all of this is squarely idol's fault, no doubt they should've told her to scale it down or fuck off. But not delivering and picking this goals in the first place is also strictly her fault