Part 2 of 2 due to character limits
Uneconomical is a slightly different question. I don’t think you can call meat “uneconomical” in today’s context because it’s being produced profitably. I suspect what you might have meant is that it is not sustainable. It’s not, long term.
I want to point out, though, that meat in not inherently uneconomical. Something like grass-fed beef allows the conversation of grasses and other plants humans can not eat into meat that humans are able to eat. In certain contexts that actually is economical, which is why there have been pastoralist societies, or societies that were hunter-gatherers on grasslands.
On a plane of 7 billion (give or take a hundred million) a meat-heavy diet is NOT sustainable long term even if short term it is economically feasible on some level. It’s the scale of meat production that is the problem more than anything inherently wrong with meat.
A comparison would be whale hunting: as practiced by arctic peoples it was never a threat to whale species. The threat of extinction came from industrial whale hunting. That’s what needed to be stopped. Subsistence level whale hunting continues on a very limited basis and has not interfered with whale species recovering populations because by its very nature (shore-based small boats) it’s not going to wipe out a species, and due to its dangers even those who still practice it are not constantly going out, it’s a once-a-year type activity (or even less than that).
(Note this is different than the ethics of hunting whales, it’s a point about the sustainability of whale hunting, not whether or not it’s a good or evil action.)
But no, I don’t think meat will become “obsolete” in the sense no one will be eating it. I do think the world will have to, of necessity, move to a more plant-based diet overall. Meat might become like hunting or gathering wild foods is in our current world - a niche market at best, possibly heavily regulated to manage resources, with very limited appeal to most people.
Right now, even those of us who like to eat wild meats are not (usually) eating them constantly - due to the nature of hunting, regulations, and so on the cost of obtaining wild meats is significantly higher than the price of meat and fish cut up and wrapped in plastic in the store.