Forbes's master cylinder change is a good example I think of some need for regulations.
Not motorcycle related, but an example I always think of is lead paint. Until 1978, we were still covering our buildings with neurotoxins 25% of the time. There's no good way of dealing with it later. You'd THINK people would stop doing it on their own accord, but it took regulations to finally put an end to it.
My problem with ABS is that it tends to be locked in. I can access most information inexpensively on my GM minivan with a cheap OBDII reader and cheap software. But I can't activate the ABS pump without their expensive proprietary tool.
Motorcycles are typically much worse, and you need their expensive proprietary tool to access ANY information.
If they're going to mandate this, they also need to mandate a physical switch to cycle the pump, and a switch to disable ABS completely (manufacturer doesn't get to decide if I take my bike offroad). But they aren't going to.
Also, no already existing equipment on my still-in-production bike. They've made changes EXTREMELY conservatively, which was a selling point for me. So late 80's technology only.