Follow up to this:
As an example, this could be the Sims "High Fashion" expansion (maybe a stuff pack, not a full EP). But in it, you introduce the fashion design career, model career, etc. Add a Paris or Milan-esque world to navigate and live in.
You could have a new fashion design learning path at uni, or just introduce a fashion school for teens / young adult sims.
You could have the fashion design career, whereby the primary goal is to grow a successful haute couture line, similar to a small business in business & hobbies, restaurant, etc. You could design trends similar to the style career already in game.
- Within this track, one of the main ways to increase prestige would be to design and host successful fashion shows as a new event. Similar to prom, a wedding event, etc., you would need to pick out the venue, hire the talent & production team, design the set and clothing line for the show, and it would need to pass muster. Attendees would either give good reviews or not (similar to a lot of other functions already in game).
- If you develop a successful enough haus, you could even have some function for "archival" wear; i.e., a notification after a show that says "congrats, this was so successful that sims are dying to get their hands on it. This collection is now archival" or something similar.
Then you could have the fashion model career, which I detailed above. It would take a lot of notes from the Acting profession already in-game. Very similar functions, just a different output / venue.
There's a ton of potential for CAS and Build items if this was a pack as well.