> Adding a new rendering backend to a games engine is a trivial task
You keep saying this, but it remains false. If it would have been so trivial, studios wouldn't have hard time adding such backends and wouldn't need to hire third party porting experts when they decide to do it. You can see how long it takes major engines like Unreal to make a fully functional backend (since features added to such engines are publicly communicated). It's very clear it's not trivial at all.
And MS and Co. obviously do all they can to keep this difficult, that's the main idea of their lock-in which they designed to tax developers with.
What's bad though, is your justification of this practice.
You keep saying this, but it remains false. If it would have been so trivial, studios wouldn't have hard time adding such backends and wouldn't need to hire third party porting experts when they decide to do it. You can see how long it takes major engines like Unreal to make a fully functional backend (since features added to such engines are publicly communicated). It's very clear it's not trivial at all.
And MS and Co. obviously do all they can to keep this difficult, that's the main idea of their lock-in which they designed to tax developers with.
What's bad though, is your justification of this practice.