When it was developed it was assumed that the cost of cellular equipment and, in some countries, the regulatory hurdles required to get authorisation to purchase radio transmitters that operate on licensed bands would make it almost impossible to do this.

I worked in a company that had a base station emulator in their testing lab in 2008. I can’t recall the cost but it was well over $10,000 and only worked with direct antenna coupling, it couldn’t broadcast.

Now we have software defined radios.