That said, there's a potential twist here. Apple's upcoming Photos app can go one of two directions: Apple could, as everyone seems to be assuming, go the consumer-focused route and stay out of Lightroom's market. On the other hand, Photos could pack all of Aperture's pro features and more behind an "advanced mode" UI. Suddenly, Lightroom isn't just competing with an Apple product, they're competing with free.
Similarly, look at many current System Preferences panels in Mac OS X. The basic stuff most users need is up front, and the rest is hidden behind an "Advanced..." button.
I conclude that having an advanced mode, or various enhanced features accessed in different ways from the standard UI, is not inimical to Apple's approach or UI philosophy.
I just had this burn me when I got a new camera (Panasonic GH4) and I couldn't import a thing. Even worse is that I was on a road trip and didn't have a way to install the software that came with the camera (also terrible, but I took photos at Yellowstone and badly wanted to see them). As of the last week an update came out and now I'm good to go, but if you want to remain on an old version of Lightroom it can indeed be tricky.
None of the other programs you mentioned are anywhere close to Lightroom. For example, while RawTherapee can technically open images from my new camera, it displays them incorrectly. They're not even the right size and I don't want to talk about color.
I think they've already done that, a few months ago.
I myself have forked for the PS + Lightroom subscription -- and I hate subscriptions --, and the reason was, that, if I am not mistaken, you can't use the Lightroom app for iPad without the subscription.