Why I've always the impression this series is a flop, but then it turn out to be a success in the long run and now is even at the third entry? Same for Riders Republic, I tought it was a complete flop, but they are still supporting it with new content like skateboarding so i guess is making some money.
Different from most publishers Ubisoft generally offers long term support to their games. Just look at games like For Honor, Rainbow Six, The Division 2 was brought back from the dead, and The Crew 2 is still getting an event list even after the sequel came out a month ago.
At least buying this I know it won't be a dead game or be discontinued like Forza Horizon games tend to do be in 2 years after release. And this comes from a guy who highly advocates against Ubi Games, but I am fair. They do provide support and can make a 180 of their games' initial release (they did with Rainbow Six and look how popular it is).
I say, pick this up now or wait for better discount in 2 to 3 months because of black Friday, and holidays. You probably won't regret the purchase, and you can try the free trial as well before committing.