To make writing this out easier, I'm calling people who have five foundations of morality Fivers and people who have two Twopies (which I'm mentally pronouncing as Two-pees).
If this question were explicitly about two hypothetical people in conflict, one a Leftist / Progressive and one of whatever we're calling these five-foundation people (Fivers?) then I would question your initial assertion about one 'cucking' to the other. It would at least be worth assessing just how true that actually was. But this question is in the context of current day society in the West and that changes things.
Simply put, the Leftist / Progressive people have a lot of institutional power right now. It's hard to argue that people with power tend to force those without to defer to them - that's what power means. Whether you are Left or Right, a Twopie or a Five Foundationer, when there is a higher cost to speaking out for you, most are less likely to do so than those who have little cost or even reward for doing so.
Note, I'm not saying there isn't more to it but I think that's an important factor that has to be kept in mind. James Damore didn't lose his job because he was wrong, he lost it because he spoke out.
Now we can branch in two directions - one to explore WHY they have more power and if that's a factor of the different moral foundation. And one to explore how it might influence things in general outside of the context of institutional power. I only have time to dip my two in the second one right now.
It's been shown that Conservatives understand the Leftist viewpoint but the Leftist doesn't understand the Right's. There are different levels on which debate exists. One common level is where the Fiver attempts to explain how X impacts on 3,4 and 5 to the Twopie. Which doesn't work because they don't care about these things or even view them as negatives because they impinge on what they really value which is 1 and 2. It doesn't work well which is why some on the right are sort of giving up and just turning into the "Yes" meme. You can also have more in-depth discussions and show how 3,4 and 5 ultimately lead through to impacts on 1 and 2.
The thing is, the more involved an argument, the smarter participants need to be to understand it and to engage with it. You can't have a detailed discussion of how 3,4 and 5 are important to 1 and 2 with someone who isn't themselves smart. The thing with the Leftist positions is that they're often very effective in a simple way. Now you can get some very intellectual people on the Left who can and will debate to a degree few can keep up. And they're not necessarily wrong on any given topic. But separately there also exists the very simple fact that it's hard to argue against a purely emotive argument. "These people are desperate. Let them in". Leftist positions often work very well as emotional arguments and means to cast someone as selfish, uncaring or bigotted. And in modern society these things are reinforced as automatic lose conditions. We live in democracies - demonstrating someone doesn't care is an automatic "Win" button in any debate. The Leftist doesn't need to prove someone wrong - they need to prove that they're bad. That's a lot easier (to a general audience) than a detailed debate about cause and effect.
I took that test posted above. I come out higher on Fairness and Caring than what it says is the typical Conservative position. But I'm not lower on the other things unlike the Leftist / Progressives. I think what someone said about you learn these additional foundations as you grow older and kids really just start out with 1 and 2 is a fairly accurate take. I was more Left Wing when I was younger. And I remember noticing how older people went Right Wing with age and promised myself that I would 'never lose my principles'. What I wasn't prepared for was that it turned out not to be caring less, but changing my mind about what actually worked.
Individualism was brought up earlier. Here's the interesting thing with Individualists (if I understand the term correctly and would categorise myself as one). Individualists do care about others and do care about the system. But they want the system to be built so people like them can flourish. And I guess Leftists want the system to be built so that people like themselves can flourish. With rare exceptions, that's what people in any camp want.
What do I want from a system? One that allows me freedom to be healthy, happy and productive. I guess the Leftist would say the same. So why do we differ so much? Because we need different things to achieve that. I want a roughly rules based society with equal opportunity, meritocratic and other than that to get out of my way and let me achieve. What does the Leftist want to achieve it? Something that will take care of them and advance them and make sure 'they get their share'. And perhaps one that gets even for them with those they feel have wronged them / make them unhappy.
It's hard to talk past my own prejudices. I feel I'm talking both about the Two vs Five foundations and not at the same time. The relationship between this psychological foundation and what I typically think of in terms of "I want a strong daddy / teacher who is on my side" mentality of much of the modern left (as I see it) is something complex and I'd love to hear other's takes on it. The Left has been subverted and weaponised over and over. Is it fair to judge an entire position on its modern form? You can argue socialised healthcare is a better approach than America's monopolistic subverted market approach without being a bad person or an idiot. We could equally add why is the Left's moral foundations so easily exploited by powerful interests? (And also debate whether the Right is any harder to exploit). This divide is deliberately enhanced and exploited in order to secure power. That's pretty much inarguable.
Kind of off topic, but does anybody know of any right wing (not conservative) news sources, as in values 3, 4, 5 but not 1 and 2? I know there's Daily Stormer, but what else?
Right Wing isn't a
lack of moral foundation for Fairness and Harm Reduction. That's more like the American version of Libertarian, according to this theory. This theory is saying that the Right / Conservative has
additional moral foundations it balances with them.