That's a very superficial way of looking at it. You could look at it in an even more superficial way and say, that this is the 17th (?) trackmania. But this way of looking at things will consistently lead you to missing the point of things.
You actually don't pay for the game. You pay for using Nadeos servers and for future development of the game. Something that did not happen for the 16 other trackmania games. These are the 2 choices available:
(a) A new release every 2nd year, but older games don't get any updates.
(b) Only 1 game is released and it gets updates and new features regularly.
An option like "buy once, get your game updated without extra cost" does not exist. If you prefer (a) then there are 16 trackmania games for you to enjoy.
Have you ever played a competitive game on a server? Toxic players hurt communities and it's better to have their toxicity in a forum like this than in the game itself. Those who pay for the game are less likely to risk their account.