@Lester Cordell Presumably you would sell old stock to bring in new stock. Sure you're not going to make all the money back, but some. But even then, you should be able to take an old driving sim, update the software, and reuse. But that doesn't seem to be happening. 

 I saw a Street Fighter 2 Turbo machine in a fast food place, in the city.  Probably the best niche for an arcade game these days.