Exactly. 50% - compared to what? Weren't all these people accepted to prestigious colleges and ~100% likely to go to college? Or, was there some reason to think in advance that 50% shows the program is a failure while if 40% would vindicate it?

The more interesting question is, what are the 50% who don't want to go back doing now? Those are the ones whose circumstances would tell us something meaningful about how well the Thiel thing is working.