Yeah, I think I was among those who sold their PoB straight away, until recently did I start staking.
I don't know why others sold theirs, but I did because I had a fee I wanted to pay for in school, and not actually because I don't like staking.

Rewarding users with delegation only instead of a liquid PoB may help to some extent but may not be the solution to the problem. My advice is that you reward half the prize in delegation and half of it in liquid pob. It balance both the interest of some users who prefer just little PoB and your goal to have people stake the token.

Thanks.