Im saying these games are still getting instalments because they still had lasting fan bases. Take the Sega "Power Surge" for example, or the upcoming movies or Golden Axe TV series.
Yes, because NiGHTS, Golden Axe, and Crazy Taxi merchs and t-shirts still sells well (unlike Vectorman, Ristar, or Billy Hatcher).
You can still found them in Amazon easily.
That's the proof for the higher ups to explain that franchise is still having potential ... their fanbase is still willing to throw money at them on merchs and t-shirts.