It's generally true that technology improving actually increased work load for the working classes. Major concessions for leisure time came from active organization and resistance, as concessions to prevent revolt (especially when near the USSR, which was more advanced in social safety nets), or via imperialism, using the global south to subsidize the global north's living standards.

This is all true of capitalism, but of course technological development within socialism can and does serve the working classes. The advancement of technology is critical to reduce work load and increase living standards, and as such socialist society needs to place an immense amount of effort on the technological front.