> Most apps nowadays have desktop and mobile variants, and you want some consistency, as you don't want users to relearn everything when switching variants.

I don't think anyone actually asks for this. The driving factor seems to be saving cost/effort by making only one design with extremely minor adjustments at best. It used to be that desktop was the main target now its mobile.

The consistency I want is between different applications on the same system but barely anyone cares about that - and many developers actively want their programs to stand out.