There's plenty of software that straight-up doesn't ship on the App Store. One could even argue that the Mac fosters it's own class of unique software since the App Store tithe is optional. I don't think Pro Tools or Steam would get Mac ports if Apple enforced the App Store limitations on their entire platform. It's trivial to imagine businesses that become viable without strict vendor pricing control.
Steam is just a marketplace for apps and just like Adobe’s suite and Microsoft Office you can buy a subscription outside of the App Store and your apps work everywhere.
And since plenty of companies do have viable businesses on the App Store, doesn’t that say more about your business idea than anything else?