Gov't control of prices has worked so well in the past, so why not...?
Prices are marked up on costs. Goods and services are sold at what the market will bear. Low margin products would need to be priced higher, but typically they benefit from competition and low labor costs from overseas manufacturers (and anything that can be imported for cheap, already is, and won’t displace jobs from a country with a strong currency)
This sweet spot may give a large gap for reducing the margins, while the consumer budget may not allow for raising the prices.
All in all, companies will work hard to find a way to stay profitable, and your tax will benefit from that.
But as an elected representative it's better to take that money and spend it, and claim the credit for the results of spending their money. Having had at least a bit of a think, I can't figure out a way to have a decent political system that doesn't trend to infinite spending.
How's that working out for San Francisco?