I’m not even talking about app design though, this problem is more fundamental than that.
At the end of the day, every app is made of a toolkit of pre-built widgets like buttons, lists, switches, etc. The stock “tab bar” component in iPadOS is terrible, which makes it nearly impossible to design a good iPad app with any kind of tab navigation without resorting to just building something nonstandard completely by hand.
This isn't profit-driven bad design. It’s just bad design.