Seniors are usually not driven towards adventure and investment and prefer stability and a comfortable and stable pension even if it is not very large, and since governments always warn that Bitcoin is a very volatile asset, I expect that they do not like risks.
Also, old people do not like modern technology and think it is complicated, so they try to stay away from it, for example, here in my country, most of Seniors still keep the old Nokia phones with buttons and refuse to give them up or replace them because they think that modern Android and iPhone phones are too complicated.