I've objected to the claim it's the government involvement that's necessary for the interest to be present and that without it the interest and people holding it "do. not. exist."
You've misidentified the people and have stripped away their names, professions, and experience, thus creating a strawman. Scroll up and look at the part of my text that you carefully did not copy and paste: those people were not merely interested. Those people were archaelogists. An archaeologist has a cachet that is very different than someone who is merely "interested." Archaeology is also not a craft that pops up in the historical timeline before concepts of history and historical analysis do.
And your interest does make the policy -- once a group with given interest is significant enough in terms of numbers and/or other kind of influence, that it becomes obvious to either the government or people trying to become one, it's beneficial for their interests to make supporting your interest the policy.
That's just completely false. I mean, the world is worse for it, but that's just false. Majorities in the U.S. want Medicare For All, but rightwing leadership in both parties hate it so it dies hard. Majorities in both parties want some gun reform that keeps guns out of the hands of schitzophrenics (yes, both parties) and no bill like that can make it five feet before being killed. Majorities poll big numbers on dozens of issues that won't be considered or pass. Majorities are against plenty of stuff that does pass -- like the second Iraq war. And all that is an ostensible "democracy" -- how much more ludicrous is that position in a
monarchy. Interest doesn't even remotely make policy.
(Hell, the Taliban blew up a bunch of ancient statues precisely because there was interest in preserving them -- in other words, the interest created the relic's destruction. A lack of interest would have saved those cultural artifacts. In anti-democratic governments, spite may well have a stronger hand in public policy than public interest.)
And history bears this out. Remember my example of those cities taken apart, brick by brick? How could that have happened, over and over, for several thousand years if mere "interest" prevents it? Where were the spontaneous archaeologists that made thousands of years of repurposing, tomb robbing, and imperialistic theft impossible? For every villager that wanted to preserve ancient structures, there was another that needed to build a nursery for their kid and they weren't going to shlep all the way to some quarry to get the bricks, so ancient history can suck it.