Yep - cell phone carriers enable/disable capabilities for a variety of reasons. Most of them probably not consumer focused. We are on Verizon for a number of reasons and the new Samsung Galaxy S8 line is probably the easiest I've seen relative to hotspots. Still can have up to 10 accesses, wifi share, unlimited data (sort of - I had the original unlimited), etc. I've looked at iPhones (DW has had multiple versions of them) but they just are not robust enough for hotspots.
Again - just our experiences based on traveling 2 months a year with 3-5 grandkids, 5 TVs, multiple tablets, GPS and so on; combined with the DW's and my use the other 7-9 months a year. Lots of data going every which way.
US Army Retired - Loving The Road Trip