In all of these discussions, I think the one aspect everyone forgets is the fact that Ham frequencies are basically "idle" frequencies, or "deactivated" frequencies for government/official use, in a broad sense. Like a mothballed battleship that can be brought back into service if the Navy says "hey, we're taking that back" and then do. You aren't driving the old beater truck in the family, so you give the keys to your kid and tell him "when we have to haul in trash to the landfill, I get those keys back".
During crisis or emergency, the Amateur bands can be quickly restricted and controlled. Controls and priorities can be set, Hams can be kicked off temporarily and told to come back afterwards. If anyone, from civilian Hams volunteering to help during a crisis, to the government itself using the Ham bands, the fact that it is Amateur and allotted the way it is means it is clear for emergency use at any time.
To put it better, the reason that Ham frequencies are safe HAS LITTLE TO DO WITH THE IMPORTANCE OF AMATEUR RADIO ITSELF PER SE and everything to do with the concept that WE AREN'T BEING SO MUCH ALLOCATED FREQUENCIES, BUT RATHER WE ARE ALLOWED TO PLAY ON THE FREQUENCIES THAT ARE CLEAR AND ARE LET TO SIT IDLE ON PURPOSE.
If you want to have an open field in an area left to be just an open field, so you can use it for a staging area during an emergency let's say, you will allow kids to rough house, play soccer, make makeshift baseball diamonds and play on it. That's OK, all of that does not hurt the open field. But what you don't want are a bunch of buildings and infrastructure built on the field, lest it must be razed, or moved, or worked around.
Ham radio is, in some ways, and not to disrespect the service at all, the kids playing in the staging area field. The industrial/commercial entities who want to buy allocations are basically trying to build buildings and infrastructure on the parcel, and this is not good. So the kids will always be allowed to play soccer there, and nobody will ever get the lease/purchase to build a warehouse. In a very rough analogy.
HF has too much interference for interest, and too little bandwith. Beyond that, some will be lost due to the modern "wireless" trend of everything. But even then, the government would rather keep plenty of bandwith "idle" then to sell it all off.