You math is correct but could be simplified. Your data looks about right however the typical 2br today is nicer than 30 years ago.

There are a few things wrong with your logic:

(1) Housing is only a fraction of spending and general inflation has been much lower than housing inflation. Most economists would use a measure of general inflation, such as SF CPI-U, to do this kind of calculation. SF CPI-U is about 210% of its 1988 value which implies inflation equivalent minimum wage of 210% * 4.25 = $8.93. You could argue that SF CPI does not capture housing expense properly and I would agree.

(2) Luckily actual wages have gone up much faster in SF than in inflation. In 1988 median household income was under $30,000, today it is over $90,000.

(3) Rental price caps, like all price caps, lead to shortages which lead to even higher prices in the future. If apartment builders knew they would only get $2,600 for a 2-bedroom, no rental apartments would ever be built. The revenue can't justify the construction cost (this why we exempt new construction from rent control). And if landlords could only get $2,600 for a 2-bedroom, many would simply live in those units or sell them as TICs (this is why rents reset on vacancy and evictions are controlled). Price caps are actually one of the causes of high housing costs in SF not the long-term solution.

(4) Life isn't fair and times change. There is no reason you should have the same suitably adjust rent as someone had in 1988. If you want to live here you simply need to choose a profession that pays a good wage. There are plenty of jobs and opportunities for training and education. It is unrealistic to think you can easily live here making minimum wage as a low-skill job. SFGov alone costs more than $28,000 per household. All this "goodness" doesn't come cheap.