The commerce clause grants Congress power to regulate commerce, not engage in it. Or are these just rather steep licenses to engage in using the spectrum. Once bought, are they transferable, without government permission and other equally steep fee, or do they "belong" to the purchaser. If the latter, Congress is engaging in commerce, otherwise they are regulating it. Regulation should be on a first come first served basis. If the licensee wishes to give up the license for whatever reason, it should go back into the pool, not be an "asset" for sale.
And the FCC can engage in commerce.
The entire thing is set up in this manner to be perfectly legal. And it is.
They are bidding on licenses to use the applicable spectrum. If the granting of a license isn’t part of what it means to “regulate commerce”, then I don’t know what is.
I don’t see any issue on this one.