While I am also not a huge fan of their DLCs it does actually make sense.

The base game is still a good game many many years after release and it’s even better now than it was at release due to the free updates that come with the paid DLCs. There is also little reason to buy every single DLC at once or at all. You buy the ones with features you like. And there are obviously sales too. Don’t buy at full price! Everybody knows that.