Most don't look as if they need funding. They are amateur productions, and many are just talk with maybe a tabletop demonstration of something, plus stock pictures and other video clips thrown in. Like this one of Wendover's. I have recorded and uploaded a couple of videos to Youtube myself, and it cost me nothing.
That has to be the rudest comment ever. You say its costs you "Nothing" but actually with every video, even the most basic, there is the cost of time. Let's take your example. The time filming, editing and uploading. Thats good you do it for free but imagine doing that every week in your free time.... for free.
On top of that, you have many youtube videos now, like this video, that goes beyond the basic "amateur" production. Add into that the cost of the stock footage (you need a subscription), writing/researching the script, recording the audio, the equipment to record the audio, the editing software costs (I can guarantee he is not using windows movie maker), the cost of the animations (even if someone does it themselves they need the time, skills and software to do it), creating the thumbnails and uploading a brand new video every week/fortnight.
Personally, I find his videos informative for a broad audience to discover a new topic every week. They are a good introduction to something for a viewer to then discover more if it interests them. Personally, most videos on youtube are far better researched and put together than some of the poorly researched tripe on TV. I find it funny no one says that they should produce content for free.
Using your theory should Journalists work for free? They can do it at home with no costs involved. What about music? That could easily be made in someone's bedroom now, should the singer do that for free? Should radio presenters do it for free? How about this forum? Should this be run for free? You do realise that there is advertising on this site?
I find it annoying that you completely dismiss someone's video which gives the average jo a really good insight into a new topic every week just because it has a 60-second advert AT THE END. You don't even pay for the video!