I can imagine a world in which Christian nationalist theocratic fascists get everything they want. I can imagine a cartoonish version where Young Earth Creationism is taught in every classroom, and all textbooks that teach the contrary are banned and destroyed, and all scientists who disagree are disbarred or killed. I can imagine belief in evolution being systematically selected out; all remaining humans either genuinely believe that the earth is 6,000 years old or are good enough at pretending as if they do.
Because there is a selection effect against belief in an old earth, it becomes pragmatically true that earth is 6,000 years old. But that doesn't change the fact that the earth is not 6,000 years old. So I see how pragmatic truth fails to capture the sense of truth I have in mind when I say the earth is billions of years old.
Here is where I sympathize with a pragmatic theory of truth: Whatever truth is, it has something to do with reality. Reality has to do with what exists. What exists has to do with what survives. What survives is that which has the power to survive. So we get the following equation: Power = survival = reality = truth. Power just is truth. Hence why a pragmatic theory of truth is a power theory of truth.
For some Germans at some time, Nazism was pragmatically true. Does that mean Jewish humans were subhuman? Nope.
For some Americans at some time, abolitionism was pragmatically false. Does that mean that abolishing slavery at that time and place would have caused America's economy to crumble, like slavers argued? Nope.
Issues of justice show how obviously false pragmatic theories of truth are. Indeed, the only way I can make sense of the concept of injustice is that injustice is the disconnection between power and truth and between power and virtue (which is the same as saying the disconnection between survival and truth and between survival and virtue).
Insofar virtue and truth are tied to power and survival, we have justice.
When vice and falsity are tied to weakness and death, we have justice. When virtue and truth are tied to weakness and death, we have injustice.
When vice and falsity are tied to power and survival, we have injustice.
This is a consequentialist analysis of justice: When evil people get away with being evil, bad things happen. When good people are given free rein to be good, good things happen.
On a power theory of truth, there is never a disconnection between power and truth. So there is no such thing as injustice as defined above. But there certainly is injustice as defined above.
I see how power is able to enforce acceptance of falsehoods. Those falsehoods don't magically become true just because they are supported by power. A power theory of truth vindicates propaganda, and any theory of truth that vindicates propaganda is obviously false.
It is true that power = survival = reality, but it's false that reality = truth. Truth has to do with reference to reality. What counts as a reference to reality depends on what survives. When Trump says any of the insane things he routinely says, these insane statements refer only to fictional properties. They are false. No amount of power allowing Trump to get away with saying so many false things changes the fact that they are false. To be silly for a moment: pragmatic theories of truth are pro-Trump, so obviously they are false. (Trump did say something true when he said that smart people don't like him.)
Really, I bet what's going on when folks try to support a pragmatic theory of truth is that they are really supporting a pragmatic theory of happiness, which is not so much a theory of truth but rather a theory of which truths are relevant. Truths about the world that lead to my happiness are relevant (e.g., truths about how to make money). Truths about the world that don't lead to my happiness are irrelevant (e.g. truths about how many balls of yarn are in my neighborhood).
But what about painful truths, like the truth that a loved one has died? That truth doesn't lead to my happiness, but is clearly relevant to me. So it's more like: Truths that concern my happiness (and thus, that concern the happiness of those around me) are relevant to me, while truths that don't concern my happiness (or the happiness of those around me) are irrelevant to me.
So we arrive not at a pragmatic theory of truth, but a pragmatic theory of relevant truth. And this theory is true because the properties it references are non-fictional.