They are the reason for this race to the bottom. Companies buy their employees the cheapest laptop, not the best. In a way iPads are also cheap limited alternatives to desktop PCs. A lot of companies could replace their expensive and much too powerful Intel boxes with a bunch of iPad minis.
You only foresee a future in which nothing important changes, that's bound to be incorrect.
Audio professionals, who earn a living by selling music, are by definition fashion-oriented.
The new MBPs have the fastest ports, the fastest processors and the longest battery life ever. And for the first time they use the same high end video port as the coming Windows laptops. Apple used to do its own thing with video connectors and now they are promoting the new industry standard. The forward compatibility of these new MBPs is excellent, especially as USB-C and TB3 now use the same shape of plugs. What you wine about is backward compatibility to the boring old stuff you have at home. Professionals don't care about your 'sunk cost fallacy', they simply want the best laptop that's also thinner and lighter. People who prioritize compatibility never bought into the plattform with 5% market share anyway.