Apparently there's a really well thought out backstory to Dinorama that hardly anybody knows, but I'm sure the people who know this - the ones who vehemently defend Dinorama as "the best put together section at WDW" - are the only ones upset to see Primeval Whirl go. I'll be curious to see if this is the beginning of the end for Dinorama. It seems like most want to see the land transformed into something else, and with Disney's plan to add a different Marvel campus at every locale, Animal Kingdom is just begging to have a Wakanda themed area added sometime in the next few years (aligns with some fairly low key rumors).
I'm going to guess they're shelving Dinorama, at least in its current form. As you said, and Gavin elegantly summarized, the area has a rather deep backstory, but on its surface it appears so cheap and tacky it breaks immersion. Elegantly dressing up a corner of a multi-billion dollar park to look like a cheap roadside attraction has the predictable effect of giving the impression of a cheap roadside attraction, no matter how much money was spent making it look like that.
If I'm allowed to be Matt N-levels of optimistic for a moment, what replaces Dinorama may be Disney's answer to Universal's Epic Universe. Or part of it, at least. I'm going to guess they won't open a whole new gate at WDW in response to Universal, at least not in the short term, but instead reinforce each of their existing parks with big new areas. This could have been going on for some time already, considering what is underway at the other parks: TRON at Magic Kingdom, Guardians of the Galaxy at Epcot, and Star Wars at Hollywood Studios. Animal Kingdom would be next in line considering that Avatar was the response to Universal's Harry Potter success and not part of this (although it interestingly fills out a quartet of sci-fi themed lands at each of the four major parks at WDW). We could be looking at something big here. Rivers of Light and Dinorama (including the DINOSAUR attraction and the bafflingly located Finding Nemo theatre) essentially make up
a good fifth of the park, and the biggest segment of land the park has available, so there should be plenty of room for expansion. It's also the part furthest away from the animal enclosures so the attractions there could be noisy of they want. To the extent that Disney does noise, at any rate. Wasn't this the part of the park that was meant to receive the "beastly kingdom" before everything went sour in the nineties and they had to settle for the cheaper option?
That being said, Covid is kind of throwing a wrench into things at the moment, so who knows what will appear when all the dust has settled. But I've got a feeling they would have kept the attractions running for a while longer if they had been uncertain about the feasibility of this, instead of announcing the closure in the middle of the pandemic. And even if things go pear-shaped and they have to build something cheap in replacement, I've got a feeling it couldn't get any worse than what is there today. Reverchon spinners and tents on a (carefully crafted) car park, one can't really go much lower than that.