> Also I really don't get why BSD developers care to develop desktop environment with their limited resource

Because they want to: they are the limited resource, and have agency. They may allocate their time as they please, and to their own benefit and preferences. Why should they pander to yours, when you don't even use it, let alone contribute? I struggle to comprehend how such an over-entitled expectation arises.

> if they want to stay relevant

I don't think you realise the sheer scale of the unobtrusively installed BSD base, from fundamental infrastructure (SANs, routers) to home entertainment systems (PS5) and more besides.

And of course, rather notoriously, BSD origins still account for a fair chunk of the userland on that Mac of yours.