1. The idea of writing the book first (or at least the first draft) and then doing the research later is not as stupid as it seems. It is what I do, so how could it be stupid? With Mondays are Red I did no research on synaesthesia until just before publication, when I realised I'd have to give talks about it. That's a bit extreme but I have done first drafts of most of my other books without much, or any, research. Even historical novels. Yes, I might do some research earlier but only for the broad points such as dates and main events, not details.
Of course, it does depend very much on the book. But for many books, even most books, it's perfectly possible to get the story down after minimum research. And the point that the guy in the video and I want to make is that too many writers attach so much importance to the research that it actually stops them writing the book.
Let me also point out, lest you think I favour books that are light on detail, that the level of research I sometimes do, certainly for historical novels (of which I've written three) is intense and immense. I need to know how buildings were made, how clothes were woven, the material of every cup and plate, even if I never actually describe or mention them. But I don't need to know it all for the first draft. I dip and skim and am magpie-like at that stage. Later, I fill in the gaps and enrich everything.
You can also research as you go. That way, you'll only research what you need and not waste time. I'm halfway through a novel at the moment and have decided on a new scene that requires some research and a trip to London; I know I can't do that trip till later in January, so I'm just noting what I need to know or check, but writing the scene anyway. Actually, what I'm doing is "writing past the scene", sketching out the action so that I can move ahead and fill it in later. What I can't do is leave a huge blank for it: I need to know what the characters do during that scene, even if there are details I don't know.
I should also point out that one of the great things about research is that it can throw up new ideas and inspiration. So, I wouldn't want to knock that. However, if you take that view too strongly, you'll keep researching for ever because you think that in the next thing you read you MIGHT come across a wonderful story. No. Stop. Write.
2. I also hugely agree with the guy's tip about putting an asterisk at a bit where you need to do research later, and then carrying on with the first draft. That is something I learnt recently. (Or, better than an asterisk, a bit of yellow highlighting or a comment box.) Then, you don't lose the flow and can easily find the bits later and deal with them.
That is one change I made to my writing process last year and I urge you to try it. It helps switch off the internal editor and just get the damned first draft down.
So, stop researching. Now. Write the book. Finish the research later.