If APs are cheap, you can get very high capacity by deploying more APs and managing transmission power so as not to step on adjacent APs. The trick is to make the radios smart enough to make coverage good enough without having a carefully designed deployment of APs.

Hopefully we can leave the antediluvian idea of "spectrum ownership" behind.

I agree. It'd be great to have more frequency bands, but if we're all on the same wifi, what if someone starts downloading obscene amounts of data?

That's true, if one is using the same kind of radio tech that Marconi used. Fortunately numerous techniques for intelligently sharing spectrum have been developed. R&D in this area will only accelerate when applications like those described in TFA are finally allowed.