What about my analysis indicated that I forgot SR was a dystopia?
The average wageslave does, in fact, get a Middle lifestyle. Assuming the 15 Karma level Day Job, since we know wageslaves are worked as many hours as possible, they get 5,000 nuyen a month. That is a Middle lifestyle. It's also only a 40-hour workweek, which is fairly standard (it varies from job to job, but it's usually pretty close for employees).
You have to remember that Lifestyle is not just a house, apartment, or whatever. It's entertainment, comfort, clothes, utilities and more. The average wageslave has no need to buy anything outside of that.
There are celebrities and Sim stars who make literally millions or billions of dollars. Eventually, they'd build up enough to permanently own a Luxury lifestyle. I'm not saying every celebrity is like that, but the really popular and successful ones (aka, the ones that people remember and know about) most certainly can.