2D's
I would guess that as the poll is aimed mainly at the hirer just about everything you say bears some relation to the reasons why not. In fact, you've probably hit
every reason why people don't.
A while back when I was still hireing I wanted to spend a night away somewhere - "4 hours each day" was the requirement. Got round that by booking the aircraft from midday to cease flying (I was only staying in Rochester at the Post house as was) and then for the first slot on the following day. I was happy, they were happy
Now I own a share I'm lucky in that the syndicate divvies up the time on a week by week basis (2 weeks in summer). It doesn't preclude others using it providing the weeks 'owner' has no need for it but it does mean you can go away for the night or a week without feeling guilty. Not all groups work on this principal however, using a booking system akin to the local flying club, and I think that discourages nights away. If I were to ever buy another share it would have to be on the basis that I have now, not on a booking system as that doesn't always give the freedom to stay away.