I think Grunt had been around for awhile. That video is December 2013ish, and I remember trying and failing more than a couple of times to integrate it into my workflow. According to whois, gruntjs.com was first registered in April 2012.

Now, to be fair to Grunt, my workflow is usually Python or Go on the backend, and I just wanted something to manage my front-end assets, so it was never a necessity for me, but knowing there's something that does what I want it to do, while being unable to make it do the thing that it does is quite frustrating.