It's all about the cash flow. Back in the late 80's and early 90's, the classics weren't classics or collectables yet. But one thing the owners and operators understood, was they just weren't earning money anymore. Like any good entrepreneur, they would stick a different game in that cabinet to keep the cash flow coming. After all, they owned the games and could do what they want with them. Why buy another $2000 game, when they could buy a $500 kit? The cabinet, monitor, control panel and power supply were still good. But it would look just plain silly sticking the latest and greatest jamma game in a cabinet that said Ms. Pacman or Galaga on the side
Solution? Just paint them black. Easy enough and cheap to do.