User blog comment:Yourleastfavoritewiki/Stupid garbage/@comment-33508540-20180112075210

I'm not sure, maybe it's because they want to limit the number of pages... if you think about it, if every single YouTuber had a page the site would get very messy and the content would be too large and convoluted to convey information clearly. Having that minimal subscriber count may help to filter through the millions of accounts out there so that more clear, relevant info can be conveyed.

Plus having 500+ subscribers is quite an achievement for the ordinary YouTuber, and so it's probably rewarding to have your own page on here after all that effort to gain more subs.

I dunno, that's just my guess :)