Isn’t this argument basically debunked? Places like South Korea and Japan have no issues whatsoever with extremely fast wireless internet at a fraction of the price.
https://pedroc.co.uk/content/uk-commercial-mobile-spectrum
It's pretty clear that Three's spectrum is woefully lacking compared to the others, except on 5G and the LTE SDL band 32 (both not widely deployed yet).
Especially problematic when you consider that Three are the ones who have been selling super cheap unlimited data packages for the last couple of years!