This is true but in my case my first "company" imploded from the weight of all the things I didn't know I didn't know.
But does working in a company ( as an engineer I would add ) really prepares you for all those troubles you're eventually going to bump into with your startup ?
I went for the experience and I was pretty dissapointed that I didn't learn any magical new way of doing things in 'the real world'.
Well the answer must be yes otherwise I'm doomed for life. So, yes. :)