I do think this is an interesting point: the current Wikipedia policy of allowing each language's Wikipedia to evolve independently risks missing an opportunity to free certain non-English speakers from some of the unfairness that results from happening to have not been born an English speaker.
(With no disrespect to the Wikipedias of other major languages, I'm sure they have many extremely high quality articles. But I assume that in, say Math, Physics, Computer Science, the English Wikipedia is the highest quality.)
Why would you think that English content in mathematics is the highest quality in comparison to other languages? Your thinking is flawed.
In my experience, non-English Wikipedia articles are great for "insider knowledge" about topics and/or local figures who are deemed not relevant enough to the English Wikipedia editors. But outside these niches, their texts tend to be both shorter and less polished.
Source?
There is no way to reconcile those histories.