Ask HN: What is the marketshare of modern vintage games by system?
This might be related to the total amount of units of each system sold, but I think that it is not mandatory to be in a such way. It is possible some systems produced in greater numbers to be not as suitable for games like other systems produced in lower numbers. The existence of emulators also may change the things, by making the numbers of the real system not so important as its actual capabilities. Another factor which I think that have to be considered is the eventual legal issues of distributing a game for an old system if the company which owns it still exists.