Deslisting is completely normal for racing games. Forza games also get delisted within 4 to 5 years. Unfortunately it's all in the hands of the real life car manufacturers, and there's nothing that can be done about that.
Shutting down the online though? That's complete bullshit. For reference, Forza Motorsport 2, which came out in 2007, has servers that are still up to this day. Burnout Paradise (the original version from 2008) is still up and running too.
Sony has constantly shut down many game servers last few years of PS3, Vita, and even PS4 games. Where is all that PS Plus money going, Sony?
The game itself is great, one of the best racing games of this generation I reccomend it to everyone before its gone for good.
Bet with Intrinsic:
The Switch will outsell 3DS (based on VGchartz numbers), according to me, while Intrinsic thinks the opposite will hold true. One month avatar control for the loser's avatar.