Yes indeed, as you say, just buy.
But guessing purely from the number of shop made tools in the video, the guy is probably working on a very restricted budget - not that I think either the router or it's plunge base are very expensive, but that of course is a relative term and may look VERY different if the budget is indeed restricted.
I just think it's interesting to see what some people can do with just a few bits of ply, very little hardware, and (no doubt) quite a lot of time. From the look of it, that plunge base is a pretty tidy "engineering" job.