I find this hardware compatibility thing a bit of a non issue. I have a usb dvd drive and floppy drive for that matter. Don't use em much to be honest. Will be using the dvd a lot in a bit while I migrate my dvd collection entirely to my nas box. (aka dd if=/dev/whatever of=/some/file) but thats mostly an exception and desire to get rid of stupid physical stuff.

As for Apple not being backward compatible, going to have to disagree a bit. Rosetta for example kept ppc code running on intel for a long time (10.6). Apple generally will give you a couple OS release notice that xyz is on its way out, start fixing it now or planning your path. To be honest I prefer that approach. Its measured, but still decent enough to handle moving on. Now with being able to run OSX in vmware fusion i'm pretty much of the opinion the backward compatibility canard in general is kinda a non issue overall. But just my opinion really.

I will say compared to things like systemd/ubuntu I've had a lot less breaking annoyances on OSX than any other unix/os including windows. By and large it works fine. Now mind you all I do is run chrome/firefox/safari/emacs/vmware on osx mostly so not like my needs are complex. But I guess all the rapid change in apple land really kinda goes by me using it. All I do is wait for vmware to work on the new os and then its game on.

I'm rambling but basically I think there is room for both types of iteration, or even a combination.