This is just the unfortunate consequence of devs not bothering to optimize something if it runs fast enough on their own machine. Stuff that is just on the edge of human perception (100ms or so?) might become a few times slower on an older machine and become noticeably laggy.

I think there are now more tools to help with phenomenon. For example for web dev, chrome has a built-in cpu/network throttler so you can simulate a low-end device.