If upgrading were guaranteed to only take me under one hour, which including all the testing I need, I might think about. However since the process alone, even if everything goes 100% according to plan, will still take me many hours of work. Also, there is th retraining on using the new UI, which boils down to time I just don't have right now.
Unlike a majority of your users, my site is a personal/hobby site, so I am not gettng paid to upgrade nor are there any new features which my users must have. Also considering how 4 went, surely y'all can understand your user base being a little gunshy.
A shame that a small space on your servers couldn't be reserved for an archive of your older existing content, which I'm guessing is still used by some of your other customers. Guess I'll just ask question on the forum then, a much better use of your time :-)
Cheers