Sure, I dont want to understate the impact that WiFi has - its a good technology, and its great that it can be used without a license. I wish more spectrum was

Sure, I dont want to understate the impact that WiFi has - its a good technology, and its great that it can be used without a license. I wish more spectrum was available unlicensed - a portion of my income depends on it! My unlicensed radio experience is largely with 900MHz ISM systems, and I wish "its just physics" was a lame excuse. Fact is, the #1 thing limiting performance on these systems in most urban and suburban places is noise - I've installed plenty of radios capable of high order QAM that were limited to QPSK or even GMSK strictly due to noise. I'd say the noise floor in 900MHz ISM is something like 3-5 orders of magnitude higher than in similar sub-GHz licensed systems. Uncoordinated frequency hopping systems are noise-resistant, but still leave a lot of theoretical performance on the table. Cellular systems have their purpose too - WiFi is not a good technology for covering a city with internet access, as many attempts to do so should prove. Nor would it be wise to allow unlicensed use at high power - ask anyone who's ever lived in an apartment how their WiFi is, then imagine if power levels could be increased by an order of magnitude to or two.