I actually think you hit on what I was getting at in your 2nd and 4th paragraphs. Calling it "MMA" is a useful shorthand, which is all I really see most names as - they give us a little bit of information in as few syllables as possible. And as long as whatever name is being used works, it makes sense to use it. And that's how I kinda view any question about whether something is a separate "thing" or not in MA: does using the name for it as a separate thing tell us some useful information?Just tossing out there that "MMA _______ is quite different from ______" unsupported doesn't help me to understand your point. In your mind, How is MMA boxing different from regular, Western boxing? The MMA "boxing coaches" used to be just regular, old, western boxing coaches. Same thing for MMA grappling vs., say, BJJ grappling. Shoot, the techniques are direct quotes most of the time.
I agree with what you said about how most arts/styles are amalgams or combinations of other styles, I get that and it's a good point. And I also get that it's way easier to call what the typical MMA practitioner does by the acronym MMA, rather than coming up with something that attempts to explain it all, jukafuyingshudojutsuwa or whatever.
I have problem with seeing it as its own "distinct" thing, as the only thing that is distinct and... maybe as you pointed out, separable, is the mixing-up of other techniques into a cohesive whole.
Jumping off of what Gerry wrote above.... this type of nomenclature war makes my head hurt because I can't understand it. And understand, in no way is this a comment on the efficacy or lack thereof of MMA. MMA works. Use your strength against the others weakness, basic tactics made into a system. It works and I like it. Names & labels are a problem. Does it truly make a huge difference if Bill Bigfist calls himself a MMA-ist or it's intrinsic in his history? To me it doesn't, but I'm not Bill Bigfist either.