Reboots are not always a bad idea. In some cases, it can be good for a creator to rebuild something from the ground up rather than papering over the cracks.
But one of the reasons why the eternal-reboot-loop happens isn't just the sheer amount of work involved, or the boredom that results from doing the same thing over and over - it's a lack of confidence. In so, so many cases, a comic is rebooted not because it needs to be and the creator has thought up a much better solution to whatever the problem happens to be - it's rebooted because the creator has no confidence in their creation, even though it might actually be a good comic.
And rebooting isn't going to fix that problem. Rebooting is just going to put a massive workload on top of a terrible self-confidence, which is hardly a great combination. The prospect of all that work, encountering a bad self confidence and the urge for perfectionism.... well, it's not hard to see why reboots rarely actually go anywhere.
That said, there's no reason why an abandoned project can't be useful at some other point in time. I've got a silly amount of unfinished novels hidden in dusty folders of my computer - I've been known to go back to them and cannibalise them for useful characters or scenes or plot-devices or settings or whatever, and put those things into new projects that were finished. Also, no time spent creating is ever really wasted as long as you learn something from it. It's only bad when you keep making the same mistakes expecting different results.