If this hypothesis where true couldn't you just build a niche Reddit clone that is run as a non-profit. People certainly would switch if it is so much better.
Reddit’s value is in the user base, not the software or style of the site.
Sure, but the argument was about what would be different if it was run or even started as a non-profit? Tencent, for example, could still become a "sponsor" and board member and try to influence everything.