I believe the estimates done by the private entities who attempted to buy/lease BBA were half, at best, of what the county's estimates were. Like any government estimate, you first throw in the gold standard and later reduce back to tin foil.
I won't argue the ADA requirements but I have never seen a federal requirement yet that couldn't be circumvented, and that would include ADA. Yes it would be messy, but it could be done, even with the settlement agreement. Does that mean they should have done so, probably not, the building needed the facelift anyway.
I too was/am a supporter of the new arena, even though I didn't have a vote. BUT, I believed then, and continue to believe there was room in the county for both facilities, for different purposes. That doesn't mean I am not aware of all of the shennanigans that went along, or go along, with passing the bond issue to build Intrust. That includes greatly inflating the reconstruction costs of BBA.