Your totally wrong... They will buy the new spectrum to keep out new competition... Possibly using it in the future... Look at the articles on Cramming (2 Billion a year for bogus fees) Its not a problem for the big carriers to buy spectrum in the billions and not use it just to keep competitors out of their back yard..There are only a few densely populated areas where licensed spectrum is utilized and its hard to find unused spectrum... Usually if you find unused spectrum and approach the owner they will not lease it to you and if they do the fees to do so are made to prevent you from making money... They will almost never sell it...
For new spectrum going forward they should only allow bidding on smaller regions and bidders would need to have a development plan that will put the spectrum into use within a time frame of say 1 year... if their deployment is derailed and a significant portion of their plan isn't in active use then they should lose ownership of that spectrum and it goes back on the block for auction...
That will force utilization of spectrum and spur competition..