I think the team will continue developing it after the full release - adding new cars / tracks / multiplayer stuff. Which means - it should be active for many years after that.
It's already been just over half a decade, which is MAD to think about honestly. It's come all this way. I think it's still got plenty of life.
I agree. I do hope multiplayer eventually comes to the main game, that would for sure make the community happy.
I would imagine that no matter what, the art team will continue to release new maps, vehicles, and probably campaigns after full release, albeit maybe at a slower rate. alternatively, it's possible that once they release "1.0" with the full campaign mode, that they basically don't stop development at all, as there are always things to tweak, improve, make more accurate, etc. and even with that, I wouldn't be super surprised if they announce some 3rd instalment to the franchise, (hopefully actually on a good game engine to begin with).
Oh well, the community will last years after that. I realistically think that we will only be getting minor updates and bug fixes after that period.
Not sure where the connection is. Plenty of old games still have active modding communities, including ones similar to BeamNG. Honestly I assume the answer is simply "as long as it is financially feasible". The team did have some software contracts in the automotive sector; I'm not sure if those are still active or bring in enough potential revenue to supplement development in the long term. The game seems to be selling incredibly well on steam and that demand should continue in the short term, but it's not like demand is infinite either.