If a user gets disillusioned with stack-exchange business practices and they run about deleting all their accepted answers, are the answers actually gone?
Well, first off... Users can't actually delete accepted answers. Once an answer is "accepted" (the asker puts that green check-mark to the left of it) only a moderator can delete it.
Aside from that, rarely is any post truly deleted. Hidden away, where only moderators and users with more than 10K reputation points is the real meaning of the word. If necessary, they can be restored.
Beyond that, there are periodic data dumps made publicly available, so it's often possible to retrieve deleted content from those even if you're unable to view it on the site.
Also note that all user contributions are licensed under the cc-wiki license, and thus can be freely hosted elsewhere by anyone so long as proper attribution is given. So it's entirely possible to find stuff that isn't in any data-dump and can't be seen on the site if someone had the forethought to copy it prior to it being deleted.
Nothing ever dies on The Internet.