You're right, there are a ton of adjustments that would have to be made. I was just pointing out what is probably the biggest weakness for someone who takes more of a boxing stance in MMA. I also included that the boxer needs to, "learn how to mix it up" which is an understatement, but that was meant to cover what you just addressed.
My bias is in favor of Muay Thai. That's what I started training first and what I still favor when striking, so I'm certainly not trying to downplay its effectiveness. I just noticed that when I went from doing more kickboxing sparring to focusing on MMA, a lot of the tools that I had been using against boxers were more difficult to implement because of the differences in range, stance and takedown threat.
A Muay Thai fighter's stance has to change even more than a boxer's stance does, when transitioning to MMA. Stand straight up so that you can fire off teeps and roundhouses and you're going to be getting blast doubled through the mat pretty easily. The Thai plum is borderline nonexistent in modern MMA. Put a Thai boxer in the ring with a straight boxer and yeah, it's going to be elbows, knees and tosses. Put them in MMA with the takedown threat and give them both a little of of grappling knowledge though, and it turns into more of a dirty boxing situation with occasional knees and much more rarely, you'll see a few elbows. Mostly what we're looking at in the UFC today is a boxing heavy approach, with bits and pieces of Muay Thai thrown in.