Legacy software support and falls under the same boat. Going back into old code to add functionality for a legacy product is basically uneconomical to do, unless it's something you specifically promises a customer.

It's especially true because after an initial software release and support period, the team might be broken up and everyone goes to different projects. Bringing them back to add functionality or fixing non-critical bugs costs money and could easily delay new releases.

People look at these decisions as sinister, and they aren't. This is simply a case of consumers getting what they pay for: you want decades long parts availability/support? Well you're going to pay for that. You want updates software for years/decades? That's also going to cost you.