It is cheaper for a company, to run fiber to your house than to build a cell tower that handles ALL the people within that region given a certain density of houses.
It doesn't mean it's cheaper for your building to do it.
In the context of space vs ground infrastructure. Ground (including cell tower) is much cheaper. And they'll add 5G to the financial centers of the world before they add it to Wyoming.
The reason companies don't "advertise" hostpots as an alternative to fiber/cable is bandwidth. It works great if you read HN, but if everyone did it, they'd start running more fiber, or cost of cell data would go way up.