Agree with almost everything in your post, except this really depends on the route. Sometimes I board and they'll say "so you're our Mosaic for today." But on JFK-FLL flights I've seen 20+ mosaics on line.
I always do LAX_JFK and very rarely has there been more than 5 total mosaics. They treat me like a VIP (almost) always, as if I am in first class. (Eh, not AA first

On a side note, I flew their mint class a few times and definitely the best transcon business class (especially for kosher travelers!)