Especially when you consider the fact that the tools and concepts they've learned and made them super awesome were developed by people in their late 30s-50s. James Gosling was 40 when he came out with Java, Bjarne and Guido were both 35 when they came out with C++ and Python respectively. None of these guys, by the way, have stopped working.
Of course it is not a blanket. A senior should adapt to new ways as well, if they make sense. For example functional constructs have become more popular in recent years. Just because one is a senior, does not mean, that they should go on writing their sequential do-while loops (usually it would be for loops, but exaggerating here), when things could be written with multicore in mind and using map reduce style. That is not seniority, it is lack of self-education and development of ones skills. No need to join the web framework churn either though. One should understand their essence though.
But getting that out of their thinking takes time. And that is IMHO what you experience. It is disheartening that they lack the respect they should have socially independent of profession for an "elder" person.
I am in my early 40s as an architect arguing with our mixed-age teams to give me the necessary rationale before making stupid "it's different now" decisions.