It's doing well now but as the price of entry into nextgen gets cheaper we can expect mta's evergreen nature to slip slowly away. At the same time as that slips away, mrgreen could just migrate to nextgen seemlessly if a mod community can arise and it isn't taken down by Rockstar.
Nextgen players simply don't have stuff like mta and gtamp which is why so many complain about their online experience. Despite their great graphics their online gameplay sucks judging from youtube videos and comments.
It's also terrible in EA where battlefield1942 will outlast battlefield 1, plenty more examples.