I feel like Marvel maybe has more one-off stories?
I... honestly never stopped to think about it, but yes! And yes omg sometimes they'll start something with a title and then decide to change it and some things get dropped and others end but then they get revived and. Too confusing :(

I didn't watch WandaVision, so I can't say! But from the bits I heard about it, it does seem like the took some things from House of M and recreated them on a smaller scale for the show. I guess because they couldn't use all the X-Men ¯\_(ツ)_/¯