Reading books from even as recently as the early and middle 20th century, it is clear that many believed-in (or at least hoped-for) a universal and permanent 'system' of symbols - which was inferred to be rooted in an innate collective unconscious - that would reliably evoke human responses of particular types: certain symbols 'releasing' certain emotions, thoughts, behaviors, motivations etc.
This idea has mystical overtones; but also had a quasi-scientific aspect, with supposed roots in biology, evolutionary history, and the presumed structure of the human mind (and brain).
Yet there has been a striking decline in the specificity of symbolism, and its power - and the great mass of people (especially in modernized societies) have all-but completely abandoned whole systems of symbolism that as recently as a century ago seemed to be 'eternal' - part of the human condition. And among those who have not abandoned these system, they clearly have less power, are less motivating, make less of a difference.
There are many factors contributing to this - I'm sure that the constant influx of novelty (especially from mass media), changing surroundings, changing location, cultural mixing; plus a great deal of top-down subversion focused on Christianity, tradition, and related to the pervasive leftism of modernity - all had a role to play.
My own assumptions is that this overall process was driven by changes in the nature of Man's consciousness; which were ultimately part of our divine destiny - because the power of symbolism to evoke religious devotion and solidarity (for instance) was also a subjugation of Man to the power of symbol: a limitation to each man's freedom, autonomy, agency.
It seems to me that there is a direction of spiritual development at work, which is a matter of maturation from child like, through adolescent, to adult - and aiming-at the divine state of resurrected Man becoming a co-worker with God and participant in creation.
In this mortal life on earth, such a spiritual development is a maturation - but it is not a spiritual improvement - just as maturing from a child to adolescent is not always (or usually) an improvement... Rather it is a new set of challenges and possibilities, and maybe more people fail to respond well to these changes than emerge as better people.
Growing up is a very risky business. Nonetheless, it is what we must attempt, if we are to reach higher spiritual levels - which is what we are alive for.
My point here is that we have an enormous cultural residue that assumes, in the face of current experience, that symbolism is an intrinsic 'fact of life'; that both for better and worse, certain symbols evoke certain human responses.
People on the side of God therefore deploy Christian symbolism where possible - putting crosses, ICHTHYS fishes, Bibles, performing public rituals, building sacred buildings. But they seem to have little effect - if any.
On the other side; those against God continually try to co-opt and subvert Christian images; making crosses a fashion item, of deploying them in subversive contexts such as body-mutilations, or inverted, of being used in publicly-demonized rituals (such as the US fake-PSYOP which is the 'Klan'); of making the rainbow a symbol for sexual perversion and the agenda of child abuse.
And this kind of anti-Christian symbolism seems (and obviously) far more effective than the traditional usages.
What all this seems to imply is that insofar as symbolism is still a significantly powerful and motivating force for Good, then it is revealed as being more individually-rooted and much less innate and universal, than was supposed a few generations ago.
Speaking for myself, the symbolism of JRR Tolkien's Lord of the Rings and its associated works is very powerful - and for Good; yet I recognize that much of this is due to my particular personality and experiences - and that for the great mass of Tolkien fans/ critics/ scholars, there is no apparent positive influence of Tolkien.
Most Tolkienites are on-side with the most strategically-evil aspects of current totalitarian materialism; and they deploy Tolkien's symbolism in support of mainstream social evils.
I am Not saying that symbolism should be abandoned; because we need all the help we can get!
I intend to make the best possible use of traditional Christian symbolism - where it works for me, and has not been spoiled - as well as Tolkien, and many others.
But it would be unwise for a Christian to rely on symbolism, or to put it at centre or root; because it will probably weaken over time, and may even be inverted in its significance.
We each need to be able to discern when that which used-to help is now starting-to harm; and be able - spiritually - to step-away from it.