Larry Sanger, who cofounded Wikipedia, left Wikipedia to found a competitor named Citizendium, where experts were supposed to play a greater role than on Wikipedia. It failed.
The Encyclopedia Britannica, which had articles exclusively written by experts, was also outcompeted by Wikipedia.
It's unlikely that Wikipedia is going to change its model to give experts a greater say than they already do, but it would be interesting to see if another expert-curated encyclopedia could eventually compete. Maybe if some incredibly well-funded company like Google or Apple got behind it it could work (though that reminds me of Microsoft's Encarta, which also failed).
Britannica is still running, I use it. It certainly doesn't have as many articles nor eyeballs as Wikipedia, but as I wrote above, it's a damn sight better. This outcome would probably have happened - as the example you've given shows - regardless of whether Britannica (and other existing encyclopaedias) had used a different pricing model, which really shows that they're not in direct competition. Same sector, different consumers.
I might be remembering wrong, but wasn't Encarta mostly offline (or at least, it required an offline installation)? I vaguely remember my family having an Encarta CD among all our CDs in the computer desk drawer; it must have been the late 90s or early 2000s, so I was still pretty young, so I might be remembering wrong. Did Encarta ever try to go fully online? I feel like that's one of the big reasons why Wikipedia was able to grow so fast; being web-based means that anyone can access it with software they already have installed and share links with their friends/family with very little effort. Maybe there was a way to share entries in Encarta, but I have trouble imagining it had as little friction as just sharing a URL.
The Encyclopedia Britannica, which had articles exclusively written by experts, was also outcompeted by Wikipedia.
It's unlikely that Wikipedia is going to change its model to give experts a greater say than they already do, but it would be interesting to see if another expert-curated encyclopedia could eventually compete. Maybe if some incredibly well-funded company like Google or Apple got behind it it could work (though that reminds me of Microsoft's Encarta, which also failed).