If you have nothing to show for it, you haven't actually started a startup. You may not get a 7 figure bank balance to show for it, but you'll get something out it. Be it a website you can show off, better anecdotes for job interviews & parties or a network of new friends.
That's kinda how I feel about corporate gigs. You have stuff to show for it, but there comes a time when you realize most stuff doesn't really have lasting value.
And to those who suffer a bad gig to have money to do the things they really love: well, it's funny how little money most of those things really require.