The FCC's job is not to get every last penny for every last Hz, it's to be a good steward of the commons.
There is utility in the general public being able to use more unlicensed spectrum at home and in the office.
We can argue about what the right breakdown might be, but I'll start by asserting that ~3 GHz in total between Verizon, T-Mobile, and AT&T, vs. only 250 MHz in total for the entirety of local, short-range wireless communication is absurd.
On Wi-Fi, everybody just shouts at each other. On mobile, providers buy huge swaths of spectrum, partially as a monopolistic strategy to make life harder for competitors, and partially because they're still using cell allocation strategies from the '80s. They maintain exclusive rights to blocks that they are not using in a region, because the towers two cells away are using them, and it's just easier to use a fixed checkerboard allocation.
Both Wi-Fi and 3GPP standards can and should be improved to make better use of temporarily unused spectrum.
A good start might be to prevent carriers from having exclusive rights to any spectrum. At least one layer of the cellular protocols should be standardized across carriers allowing towers and phones to dynamically request and then relinquish spectrum on an as-needed basis.
Today, if 500 people in a room use T-Mobile phones, but Verizon owns all the spectrum, then nobody gets to use anything. This is stupid. Verizon should have access to a fraction of spectrum proportional to their users in an area. More users, more spectrum, and vice versa.