Rotating stair case / transporter / smaller stair case

Well in the past spiral staircases came near the end of a series. I don’t believe we got them in TS1 until Superstar, and in TS2 it took until Apartment Life for them to make a reappearance. In TS3, they came part way through, with Generations. So they have always dragged their feet about introducing them. For me they are not optional; they really ought to be treated as essential building components.