I don't know how this related to robocall, but I like the question!
I can only answer for Denmark, but there we have a thing called "ratepension" which I think is similar to a 401k. Retirement age in Denmark is 73 and the public pensions do only cover the bare minimums – you also need at private pension.
In the US, the robocalls typically target seniors that aren't able to identify the scam.
In the US, we have 3 "pillars" of retirement income that we are told to keep roughly the same size: Gov plans (Social Security), personal savings, employer sponsor plans (401k).
I had always assumed in Europe, most people expected the gov to fund most of their retirement (70%?). Whereas the expectation in the US is social security only covers ~33% (although for many people its 100%).
I can only answer for Denmark, but there we have a thing called "ratepension" which I think is similar to a 401k. Retirement age in Denmark is 73 and the public pensions do only cover the bare minimums – you also need at private pension.