I don’t think it’s exclusive to startups or tech either, it seems more like a downstream consequence of the fact that there’s no real innovation anymore. Capitalism demands constant growth, and when there are real technological improvements you can achieve that growth through higher productivity. If there are none, you have to achieve that growth through other means like forcing employees to work longer or cutting costs. The alpha is all coming from squeezing the labor force right now.
This doesn't sound right to me. We are currently getting smacked upside the head by an enormous technological innovation. I believe that, even within the framework of capitalism, this problem has social and political roots. The "robber baron" period late 19th century America has strong similarities to what we are seeing today, and technological stagnation was not the cause.