I don't think we'll get another season like Horizons. FD aren't stupid.
They know that asking people to pay up front for nebulous content that's lackluster when it eventually arrives isn't going to fly again.
There's already been rustlings regards this if you pay close attention to the livestreams.
I guess their choices are
- Continue with the season model.
- Release a traditional expansion (e.g. something like The Witcher 3's Blood and Wine)
- Release DLCs
Continuing with the season model is risky as they burnt their bridge with Horizons. They may not get enough sales of the season pass to fund the cost of it's development and I think they know this going off FD's comments.
Releasing a traditional expansion would mean there's a dearth of no content updates for a considerable time while the expansion is developed. Risk would be that after all that work it wouldn't sell as much as FD liked.
Releasing DLCs would mean there's less time between 2.4 and future content drops, the risk would be less than a full expansion as they're not putting a lot of work into something that might not sell.
So I'd say the future is point releases sold separately to anyone without a LTEP. This hopefully will mean better updates from FD as they will really need to sell each DLC and provide quality rather than vaguely describing something at the start of a season, asking for as much as the cost of a full price game for it and then delivering lackluster updates because you've already got the customer's money and don't really need to try hard.