X4: Foundations is, like all the other X-games from Egosoft, an open-world space simulation with a lot of different things to do.
Most notably, you can do the following (links are to official videos from Egosoft):
Of the items in this list, the first 3 are definitely present. Exploration is there, but there is not much to discover once you've mapped out the universe (which, although not large, is big enough, especially with the current 2 DLCs added).
Strategy, although there, is mostly limited to having more ships than other factions and once you get a shipyard and produce all the materials yourself, you can easily build fleets that can single-handedly wipe out every other faction.
The think-part is the most interesting claim, there are a lot of decisions to make that will affect the entire universe, but the most profit is to be gained by making sure factions keep fighting each other as the entire economy is based on ships.
I think the game would definitely benefit from a domestic economy as well and hopefully Egosoft will implement that in a future version.
I do tend to play a lot in the early/midgame as that is where most of the plot-lines are implemented, although my current play-through will be more long-term so I can also try the terraforming options.