I'd like to politely disagree. I've worked for two startups that were not mine, and both were awesome. What you're saying might be sometimes true or often true, but to say you haven't seen any exceptions is a pretty bold statement.
Consider all of the YC companies, or every startup you read about on HN or TechCrunch where you think, "wow, they are doing cool stuff". Many of those companies have at least a few (and probably more than a few) non-founder employees. If you polled all of those people, how many would say they feel like they are exploited, underpaid, overworked, guilt tripped, etc? It might be a non-trivial amount, but I'm pretty sure it's far less than 100%
Consider all of the YC companies, or every startup you read about on HN or TechCrunch where you think, "wow, they are doing cool stuff". Many of those companies have at least a few (and probably more than a few) non-founder employees. If you polled all of those people, how many would say they feel like they are exploited, underpaid, overworked, guilt tripped, etc? It might be a non-trivial amount, but I'm pretty sure it's far less than 100%