Cloudflare protection also completely messed up federation, so in those days kbin was more or less completely cut off from Lemmy. And back then there weren't really alternative kbin instances to choose from.
Kbin is still much more bleeding edge - kbin had just recently reached a level of basic usability at the time of the first wave of Reddit migrants, whereas Lemmy has been around for years with a development team of twice the size (two people).
Where kbin is lagging behind the most is probably in how easy it is to set up an instance, and administer it once it's out there. This means that niche sites are more likely to use Lemmy at the moment. Then there's also, of course, still no API/apps (could change any moment now).
That said, I am incredibly happy with kbin myself, and I also don't mind at all most of the people out there being on Lemmy. As far as I'm concerned having two strong platforms from the beginning makes the Threadiverse stronger.
ArtieShaw