Ugh, no! It's not because they know the best places to get meat, etc. When I cook at home I can make better meals than most restaurants I go to. I pay them because they do the damn work for me!
There are some businesses where secrets matter, but the vast majority are just in existence because they have infrastructure setup to do things cheaper/faster than you could yourself.
I think you should expand your view. You are only taking into account the service aspects of the business and not supply chain or other very important details (like location).
All businesses have secrets and they matter. The cheaper/faster portion of the business is a form of information arbitrage. Cheers.
There are some businesses where secrets matter, but the vast majority are just in existence because they have infrastructure setup to do things cheaper/faster than you could yourself.