A fully cynical approach, however, would likely still find that a certain level of interest in politics is necessary so that one could optimize one's political opinions (and when and how to express them) so as to maximize their signalling value.

Ironically being apolitical people will assume your politics match theirs or at least fall somewhere on the spectrum of respectable consensus, so the difference between this and consciously maximising your opinions might be smaller than seems at first glance. There are indeed in the Western world professions where it is basically your job formally or informally to master such signalling and "know politics". But these are far from the majority, even among the educated classes. Maximising political signalling will do you some good but, consider the non-trivial amount of time, effort and energy spent on this. There is a very real opportunity cost here.

In cases of major economic and political instability, it can be tremendously valuable to be able to anticipate the coming trouble and undertake damage control as early as possible.

I would agree with this. I tried to emphasise this here:

Daily politics, anything shorter than a several decade long trend or a revolution will simply not affect you and is a waste of cognitive resources and often a source of frustration.

Looking back I think I should have elaborated on this black swan more.

Now of course, one could argue that the present system in the Western world is so stable that the probability of such trouble is infinitesimal, or that there is no known method for predicting such trouble with any accuracy.

I would argue that even in times of great instability and war it is relatively easy for most "common people" (who are either relatively politically apathetic or reactionary) to side post facto with the winning side, identifying which doesn't take much time or cognitive resources. If this was not the case several countries today should be less populous than they are.

But of course people who find themselves in classes that suddenly become politicised but weren't until recently (like people who wore glasses under the Khmer Rouge) would find themselves in quite a bit of trouble if they happen to follow such strategies.

However, this must be established separately from the issue of futility of trying to influence politics by personal activism or voting.

I should have been more explicitly in separating these two. But the thing is I don't think our mind really understands us being informed about politics and not being able to influence it in at least a small way, with the possible exception that we are really low status in our tribe (something which will frustrate us if we don't feel we deserve this low status according to other signals).