I don't think it's fair for app developers if I just leave it running idle if I am able to find a new owner who had more time for it. Also, it's a huge liability to just leave unattended (e.g. Just today, I had to do a security update for libpng buffer overflow, which could potentially haven exploited by a hacker with the thumbnail uploading).
How do you even find out about all the security updates that need to be done? This is what's personally kept me from getting involved in running an important crypto site -- I don't have the knowledge of how to keep things secured all the time.