Maybe the other 3 billion will use a near limitless supply of knowledge for something other than watching cat videos.
This is patently false. There is a whole swath of biological research under the banner of "basic science" which, while it may purport to address a far-off disease application (for the sake of grant $$$), is only aimed at understanding how life functions at the most fundamental levels. Thousands upon thousands of researchers in this country are funded by the NSF and NIH (among others) precisely to figure out things we know that we don't understand.
For an anecdote, I did this kind of research for a few years. My lab was trying to understand what the function of a motor protein was because we could see it, we could see processes it was involved in, but had no idea how or why it was behaving the way it did. There was no disease focus. Part of research is cataloging the natural world so that, maybe, we will one day use that knowledge for our benefit (not necessarily for disease).
Disease is one of many applications of basic research. The amount that goes into producing chemicals through engineering bacteria and producing food through engineering plants is staggering. These applications are currently enabled by CRISPRs. I'll be interested to see how eugenics develops in the next few decades.
If a nearby car abruptly changes lanes... the car would be alerted...
... often by physics