There would be no harm in restarting the photography competitions, there are clearly plenty of very talented photographers in this forum (as can be seen by this very sub-forum). I think TB's post is a good indication of what killed the photography comp, people are very happy wandering around town and taking photos of anything that catches their eye but not enough people have the time to hunt down specific photo opportunities. Maybe if it returned with month long deadlines and vaguer subjects it would be more popular, we can't find out if we don't try.