Yep, an LTE site can be pretty small. It's just IP traffic. A router and a radio in a box. Connect to an antenna and an Ethernet port and there ya go. Very over simplified description, but you get the idea. I've watched cell sites get smaller and smaller over the years. What used to take rows and rows of cabinets full of gear is now done out of 2 or 3 cabinets. As time goes on, this will get smaller and smaller. Smaller/cheaper equipment will allow more density and more sites. That will translate into more speed.
When all that happens, they'll be complaining about this old ancient LTE equipment and why don't we have the new XXX stuff, lets take that old inefficient LTE spectrum and do something with it. There will always be a demand, and we will always lag behind the technology curve a bit.