They recruited Dahl (and certainly contributed much through people like isaacs (npm, iirc he was at Joyent already) and more before he officially moved to Joyent) but if my memory of that time isn't all too blurry it certainly gained enough steam at that point to credit him as being the one kicking it off. It surely was the node we know today at that point (granted, with a much less enjoyable API surface). Not that this belittles their role, they certainly grew and provided a viable ecosystem for the large scale adoption that followed.

> they can be quite reliably be credited to being the company that made it happen originally

This is false, as someone who was actually there can attest. Node.js couldn't even run on Solaris when Joyent finally got involved, and Node.js technically and in terms of growth had already taken off thanks to Ryan Dahl.

Source: I'm the guy that ported Node.js to Solaris, and I have nothing to do with Joyent, then or now.