Businesses charge according to the market, and restaurants are no exception. 
If the prices were atrocious, it is likely because their costs were also high - rent being one - as your two goals are to produce high-quality food and get bums in seats. 
 I doubt even high prices at restaurants make them wealthy, given 80% of them fail after 5-years and their margins are between 2% and 6%. 
You don't get rich in the restaurant business unless you are a big franchise.