Well, no, you couldn't, because that's kind of not how it works. Power doesn't make it go faster or further. You can easily go 150km with a few hundred milliw

Well, no, you couldn't, because that's kind of not how it works. Power doesn't make it go faster or further. You can easily go 150km with a few hundred milliwatts and get 322Mbps with a few hundred quid's worth of equipment if you've got good clear line-of-sight, but you need to go to a way higher frequency than 5.8GHz. Also, don't forget that there's a difference between TX power and EIRP - when I had my amateur radio Foundation licence and was limited to 10 watts, I was running 10W at the antenna port as measured on the terribly expensive Marconi test set - but well over 150W EIRP totally legally by simply using a decent aerial. This also meant that instead of blasting everything around with RF and only hearing fairly close stations, I could hear about as far as I could transmit. Finally, I think you're grossly underestimating the cost and complexity of something that'll output 1500W on 2.4GHz, which would be incredibly expensive and difficult to operate.