There is a secondary market. If you buy out a licensee and say "hey, I can offer newer more profitable service with similar emissions" the FCC will let you.
So, theoretically, you could start a wireless company by getting some spectrum from a TV station and then showing that the emissions will be similar enough that the FCC will be fine with it.
The problem is that to provide competitive wireless service, you often need to assemble licenses for a large enough geographic area and many existing licenses will be geographically constrained. If I negotiate with Channel X in New York, that doesn't mean that same channel will sell to me in Boston. That makes it very hard to standardize a band. Worse, because of the spacing for broadcast channels, you might not be able to use a frequency in an adjacent market. Plus, how close to the boundary of the station's radius can you put a cell site?
Plus, with a UHF TV station, you're talking about a 6MHz block. Adjacent channels aren't available within a market. Maybe 6 stations in a market? The big 4 aren't likely to shut down, but are more likely willing to move, but then it's really the FCC that's accommodating a bunch of that value. It gets a little complicated.
I mean, this auction is going to be clearing 84MHz of spectrum without requiring a lot of stations shutting down by re-packing them. If you bought 4 stations in a market, you'd have 24MHz and be down 4 television stations (which a lot of people still use). By splitting off the band, they're able to use most of it rather than having to coordinate market to market with the old broadcast TV.
Honestly, I wish that the FCC could/would mandate that they can force in-kind trades for minimal money because $10B going to the broadcasters seems like a lot.
The process is easier when you own a band (like Dish) and can get the FCC to allow you to use it in a new way like authorizing terrestrial usage rather than just satellite.
Secondary markets can be great, but communication services often means band standardization and enough geographic area that people will use your service.
