I agree with you that a bid process is the best way to determine market value. I see two big issues with this.
First there would be no competition on many of the public allotments. When the homesteaders arrived, they laid claim to all the water, when the homestead act was discontinued the land that was unclaimed became BLM. Many public allotments need to have access to the water on private land to be viable. Even if there is enough water on the public, you still need access to a corral and good luck getting the government approval for even a set of portable corrals. You could lose half the grazing season waiting for the approval. Forget about a set of permeate corrals You could be waiting years before this went through NEPA and the appeals appeals. Even if you do have corrals on the public, you do not want them. Rustling is still a thing on the accessable allotments where you are miles from anything. Not common but people will still load up a trailer load of cattle and take them east of the Missouri where you don't need brand inspections to sell them. A set of corrells just makes it easy for them. There would be no compeitive bidding on many allotments. You could remidy this with a minimum bid, but why set up a bidding process that would be sure to cost the goverment a bunch of money to administer and esentualy still have the same systom we have now.
The second reason I dislike a bidding systom is on allotments where there would be compition in the bidding, the winner would likely be the opporater that is going to skimp on maintaining the allotmernt and when it was getting close to the end of the lease, they would ride that allotmemt like the rented mule it is. The goverment simply does not have the man power or money to ensure that the allotment is treated well and even if they do try to enforce the rule on a bad opporator. by the time it goes through the appeals process the lease is up and the bad opporator is long gone.Change to a bidding systom and you change the permit from something you own to something you rent. People alway treat what they own better than what they rent. There is a reason range on public has been improving since the time we changed from the tragidy of the commons to the systom we have today where the opportors own the permit. Change to a bidding systom and all the incentive is to get as much out of the allotment as quickly as possable instead of haveing something for future generations. A bid syestom would be a bad deal for the health of puclic range.