If you pop up a spectrum analyzer anywhere there are people, you'll see loads of traffic jammed into the "free-for-all" ISM bands, you'll see AM & FM radio, and you'll see precious little else. If you have a really good spectrum analyzer, you'll be able to spot the occasional cellular traffic, but by and large the spectrum that has been auctioned off to corporate owners goes almost entirely to waste.
50 years ago when fixed-frequency narrowband receivers were all we had, this made sense. It was a necessary compromise. Nobody needed bandwidth but everybody needed a dedicated frequency to accommodate their primitive hardware. Today it's the opposite, and the relative usage of ISM bands vs everything else proves it. The radio-frequency situation makes the real-estate markets with block after block of unoccupied apartments look downright efficient by comparison. We need to fix this.