To expand not refute,

> If truth is defined as beliefs which lead one to make decisions that cause you/your society to thrive

This is 'metaphorical truth' to be precise.

But it's only a part of the virality of memes, not the whole.

Propagation can occur not just due to usefulness, but to other factors such as simplicity/replicability, human susceptibility / 'key in a lock' etc.

If survival was purely metaphorical truth, then all surviving lifeforms would be 'the most true' (including viruses being 'true' to us). Which can be argued, at a philosophical level - But then we've expanded the definition so much as to lose relevant meaning at the pragmatic level.

Porcupine throwing quills, and all that.

Nice comment! I had forgotten about metaphorical truth. Sent me on a nice rabbit hole.

I think 'metaphorical truth' is correct but slightly too narrow. Pragmatic truth includes metaphorical truth but is slightly wider.

And while I agree with your assertion in the short run, I'm inclined to doubt its correctness in the long run. Most things eventually have consequences.