People really seem to believe that code is the only thing you need to make a SaaS company. It's like thinking a line cook is all you need to open a restaurant. There are so, so many other components to running a business.

I agree!

Although the proponents of this idea argue that companies will create and (!) maintain many tools in-house.

It’s not so much about running a business, since you don’t sell anything and only have internal customers.

There is also an aspect of thinking no one will go to restaurants when anyone can make the same food at home.

SaaS is mostly sales.

100%, particularly B2B SaaS