Note he actually made a point of making it (mostly) compatible with a RasPi Model 3 enclosure. Note that this has very different design choices compared to a RasPi, probably most notably the PS/2 and RCA connectors, which suggest the idea to being able to use it with older TVs or the like. As a "learning platform for underprivileged children" it's highly likely that things like RCA video and PS/2 keyboards are incredibly easy to pick up today incredibly cheaply: Everyone wants to get rid of them.
PS/2 keyboards/mice might be harder to find than you'd think. New ones are hard to find and while there are literally millions of old ones sitting around disused, their very lack of value means that the secondary market is not strong. Not many people want to bother listing a $2 used keyboard on eBay.
I'm a tech guy and could scrounge up a dozen old keyboards in a few minutes, but someone who is just starting out probably won't have a collection of old hardware to pull from.
Finding TVs that will still take composite or component is getting harder. And even if they take it, they usually only take it in at a very specific scan rate and resolution, and it usually looks like garbage.
I'm not sure where you're from, but I don't know anyone who doesn't have literally dozens of VGA monitors they can't figure out how to get rid of. Even modern this-year Dell monitors still come with VGA, and I've never even seen a modern TV without RCA plugs.
Is their a Goodwill or Salvation Army store around you? Check it out, see what their electronics section looks like. That's the target market.
Many modern monitors might have VGA still, (none I've seen recently do) but almost all lack the ability to handle the 15khz horizontal that much vintage computer tech uses.
True, VGA being an analog interface was perfect for CRT-based monitors. Many modern LCD monitors still have it, not sure about the image quality though.
VGA is still pretty adequate. The main limitation is that if you hook up a VGA monitor, you can't watch most proprietary video, whether it be disc or streaming, because they need a more sophisticated connector for their DRM schemes. VGA cables have no real difficulty with 1080p or some even higher resolutions.
