For me for a game like Sims I need a big variety of cosmetics to keep me playing, new game mechanics are kind of secondary.(Although, if I trust any company to recognize that and adjust accordingly it’d be paradox) But still, you are completely right, paradox doesn’t abandon players that don’t buy the dlc but release content patches at the same time. Plus if you happen to play with other people only one person needs to own the dlc, which is one of my favourite things paradox does and more companies should do.
Also, I completely forgot about mod support. That makes a huge difference, too.