Cell capacity is a shared resource. The reason (or part of it) that Verizon limits your speed is to let others use it too. 5G brings smaller cells and more capacity in each cell, which means less need to throttle.
One of my biggest memories of 9/11 as a school-boy was when all phone-lines were so congested that no one could call their parents. We all kept trying, but it was "busy" tones all the way through.
That's the only time I remember land-lines all being too congested to make a call, but it was part of the event that a lot of us talked about for days later. Some of the kids were trying to call their parents to see if they were still alive, because some of them worked at the Pentagon. (Their parents were fine, but they too couldn't contact their kids because all the phone-networks were too congested. I presume everyone was trying to call each other at that time).
Its the only time in my memory where I got a busy-signal from picking up a phone. You didn't even dial yet, it was too busy to even give a dial tone.
For the kids out there: texting wasn't common yet, and pagers weren't really worth the trouble. Pagers worked like text messaging today, except you didn't have a screen... so it was hard to use and weren't really used very much. You called a pager using a land-line, and then dialed "44 33 555 555 666" for "HELLO". People generally still just did phone calls for simple messages like "I'm okay".
Perhaps it's different in USA, though, the geography and population density differences mean that the backhaul problems are different than in Europe; but here the bottleneck is on the radio side.
THIS!!! Even if more sites are added, each with their own 10/100gb fiber run - it's still running to the main circuit for a region. That circuit isn't changing(in the near term), this will just consume more of it. Regions without colossal backbone access that are already bandwidth constrained will remain bandwidth constrained.
Network bandwidth is still going up and up in speed. 100G was very expensive and hard to do only a few years back, now it’s becoming standard. DWDM systems continue to evolve.
They spend massive amounts of money on marketing, at that doesn't benefit the product at all.