Of course cloth sims of varying fidelity are everywhere. Even games have had cloth sims for decades at this point.
But it is also something that remains a research problem how to do efficiently and with good results; pretty much every year in siggraph you see couple of new papers around cloth sims. For example this year we got this https://youtu.be/d9TZhtXeMio
At least solver seems faster (if not better) in later versions? p.s. My try at 'flag in the wind' in Blender from around 2022:
https://0x0.st/s/aJ6DNj2pEHzRdBiscEIsbQ/KCsK.mp4
I do remember it took me all day to get somehow realistic motion.
But it is also something that remains a research problem how to do efficiently and with good results; pretty much every year in siggraph you see couple of new papers around cloth sims. For example this year we got this https://youtu.be/d9TZhtXeMio