I too went down this path. It's hard to swallow spending $250+ per wheel, when I gave $1900 for the truck. Course I've put several thousand dollars in my 69 M35A2. But I can still easily sell it and not lose any money I've invested.
The allure of a $3000 or less 6x6 military truck pulls a lot of people in. But like others have mentioned, there's costs associated with their upkeep. And a lot of cost involved in their upgrading.
FWIW, we're working on making adapter plates for the M35A2 to fix to the hub. That will allow you to bolt on a 10 lug pattern wheel. There's a LOT of work involved in converting a 10 lug wheel to six lug via a adapter plate or a recenter. $250 for a recentered HEMTT is a steal for the amount of work involved.