I don't think we can so easily pin it on capitalism. Capitalism brings incentives that drive work hours and expectations up for sure, but that's not the only thing in play.
Workers are often looking to make more money, take more responsibility, or build some kind of name or reputation for themselves. There's absolutely nothing wrong with that, but that goal also incentivizes to work harder and longer.
There's no one size fits all description for workers, everyone's different. The same is true for the whole system though, it doesn't roll up to any one cause.
What you say is true, but the dominant effect in the system driving it towards more exertion than anyone would find desirable is the profit incentive of owners to drive their workers harder.
How do you narrow it down to capitalism as the root cause though? It seems like a reasonable guess, but our entire system is capitalist - we have no way to isolate or compare against to see how a roughly similar system would play out without capitalism.
We have seen other systems, socialist systems, that are much kinder to workers and give them more security and free time. The capitalists managed to destroy most competing examples and forced the remaining ones to somewhat liberalize via the IMF and other trade regimes, to make it appear as if there is only one choice. Not so!
Workers are often looking to make more money, take more responsibility, or build some kind of name or reputation for themselves. There's absolutely nothing wrong with that, but that goal also incentivizes to work harder and longer.
There's no one size fits all description for workers, everyone's different. The same is true for the whole system though, it doesn't roll up to any one cause.