One way to bootstrap this approach is to mirror Wikipedia and add on expert articles. That would demonstrate the value of the expert articles. I suspect this value is low. If it were sufficiently high, this Expert Wikipedia would rapidly come to dominate.
I think the Expert Wikipedia would be a bad use of resources because most people do not desire this and because experts will not deliver better articles in general.
That’s an impossible experiment because a mirror would never get the same network effects, search engine treatment, and cultural integration Wikipedia has accumulated.
I suspect getting experts to write any significant fraction of articles is a multi-million dollar experiment. I don't think it's worth it, and I doubt anyone running WMF would think so either.
We have completely expert written media in Encyclopedia Brittanica, so that's probably the best place for people who don't want to use WP because it's insufficiently expert-written. It doesn't make sense to go join that market.
I think the Expert Wikipedia would be a bad use of resources because most people do not desire this and because experts will not deliver better articles in general.