That's an interesting hypothesis. I think of it more in terms of human development over the lifespan rather than an artifact of survival bias. In my opinion, the relationship between age and conservatism is mainly because of three reasons:
As you get older, you tend to accumulate more wealth, responsibility, children, etc. so you have more to lose than when you are younger, which means that you tend to value the system that protects what you have.
As you get older, you get weaker and slower and lose the physical confidence and recklessness of youth. That feels vulnerable, so you tend to worry more about things like violent crime and disorder. You start to value stability and order more.
When people are young, they tend to be more prone to simplistic and radical thinking, simply due to lack of life experience. This is both a strength and weakness. It makes youth passionate and energetic, but also more prone to believing that there are simple solutions to complex problems. I say that recognizing that nowadays most Trump supporters are older and are very much embracing Trump's simplistic solutions, but I think we all recognize that something very radical is happening on the right wing.
I note also that these are general trends across the lifespan, not deterministic or true for every individual.