Wow

. You should read it in a context of the thread. Not as a reply to a single sentence.
Most average consumers don't buy ILCs at all. Average photographers already have a few of those. And enthusiasts aiming for advanced, more expensive cameras, actually are considering FF and 2nd-hand FF prices just make it a no-brainer.
Mantras like - "If you don't shoot in low light, you don't need FF" - are pointless. Most people don't even need APS-C, because they don't utilize the potential of such cameras. And most of them are fine using smartphones. FF is better, regardless, much better, for many things, not just low light or narrow DoF. Perhaps you are just not capable of seeing it. If crop camera is more than enough for you, that doesn't mean it is as good as FF. It means that you are posting in a wrong forum thread.
Now, it is silly to expect each new APS-C camera to be vastly superior to the one (or two, or more) you already have, at least in terms of still image quality potential. I don't know how many cameras you need to buy to understand that, I had two, your mileage may vary. But some people never grow up.
"the vast majority of cameras sold are crop" - the majority of cameras sold are inside smatphones, and the majority of people buying them are not even smart people (not judging, just statistics). It is only logical that most "me too" camera purchases are the cheapest crop cameras.
"Crop sensors are constantly getting better" - so does FF!
"and have narrowed the gap" - no, the gap is just being dragged along, in between

.
"professional results" have little to do with sensor size. If a tool is good enough for the job, then it's good enough. If it's not - you are not getting paid. As a non-pro, I don't have a separate optimal camera format for every situation possible, I just need one camera to cover all of it and the APS-C is not good enough.
"you can't tell the difference between crop and FF" - and you own both APS-C and m4/3 because there is one? It is a silly argument. Nowadays, it may be hard to tell the difference between a girl and a boy

you must always check the "EXIF" to be sure. Are you saying there is no difference if you cannot see it in a snapshot?

The point is not in telling the difference. The point is the potential, the quality, the price, the post-processing routine and the pleasure of using it. The difference is always there. And you can shoot bad images on FF too.
Don't you know that printers and LCDs are constantly improving and growing as well? Clearly your cameras are overkill for 8"x 12", because my FF gets me 24"x 36", which is 9 times larger. I suggest you try 1"

, because you won't tell the difference anyways.