That’s only true for the high-end Pi 5. Lower-powered models like the zero 2 are still cheap, and they’re a lot easier to find than a few years ago.

They aren’t very useful for much besides hobby projects. Modern hardware is more energy efficient and will be cheaper in the long run compared to anything that would be considered e-waste. The only advantage an old laptop has is the initial cost, so it makes sense for a small home server.