Something I've noticed is that a phone is actually usable at a stadium or concert when 3g or 4g felt essentially useless at that density.
AT&T has figured out a way to monetize that. If you have a "Turbo" plan or add-on, your phone will work in crowded cells.
If you don't, good luck with that.
and that has definitely improved everybody's experience at concerts /s
I've seen an interesting corollary: 4G on an airplane at the gate is much faster than the 5G microcells inside the terminal.
If I'm downloading podcasts for a flight, I do it on WiFi beforehand or on 4G on the plane. 5G in the terminal is really useful at getting you some service, but it's slow.
Probably a side effect of not enough backhaul speed.