Men no longer willing to put their amusement first is probably the biggest problem. Used to be daddy did what daddy wanted to do on the weekend and that was that. No longer works that way for almost all dads.
The other issue no one has mentioned is unpleasant club cultures. Not universal but there are plenty of them around. And the unpleasant culture may not be obvious to experienced pilots that own gliders and have a level of autonomy far removed from new students.
Solve those two and soaring will do just fine.