You obviously could do exactly that. What upsets people about the way Wikipedia is run is that they know their "better" fork would attract no meaningful usage.

this is essentially what wikia is, but focused only on specific niches rather than all content that wikipedia doesn't want to include.

if you wanted to create a wiki that included all the stuff you wished wikipedia hadn't deleted, you could. but that doesn't really solve the problem, because the problem isn't that there's nowhere on the internet to post information about topics you are interested in - the problem is that people want to use wikipedia's authority and importance to promote topics that they are interested in. posting that content on some other site that isn't wikipedia doesn't accomplish that goal.

if jessica wade didn't want her work to be subject to wikipedia's notability requirements, she could have made a blog and written a series of posts highlighting different female scientists.