I wasn't talking about gaming either.
It's not about ooh shiny new thing, it's more like the old thing is awful and the new thing addresses what's bad in the old thing. The GL API design is about 40 years old now, counting the decade when it was SGI's proprietary Iris GL, and it hasn't aged well. For at least 20 years it's been very out of alignment with what hardware is actually doing. Thanks to this impedance mismatch, GL drivers are very tricky to write if you want both performance and correctness, and you're always leaving a lot of performance on the table. This difficulty is magnified if you want to properly support all the dusty corners of the GL API spec, and there are many of them.