Soundforge on a 486 100Mhz was already pretty fast at editing a single track of audio. It's amazing how much heavy frameworks have warped our perception of normal interactivity.

I had a 486 and did some rudimentary audio editing back then.

I remember the performance to be decent, but not 60fps-decent.

But aside from that phones usually have relatively infrequent touch updates, which usually results in a single repaint on every such event, so 10FPS or so.

And took more time and expertise to develop and only worked on one computing platform. The software industry has been a cycle of trading hardware performance improvements for developer productivity since the beginning.