The insurance analogy would work if the 'premiums' were in any way related to the 'risk' (payout). Or even if they were community related like Irish health insurance. But higher earning PAYE and very high earning self-employed subsidise lower earners and most of the self-employed. That's taxation, not (social) insurance.This isn't the purpose of the "social insurance fund" though Brendan. It's rather like saying after paying car insurance for 40 years that you feel your friend should genuinely have a higher payout (benefit) then someone who has only paid car insurance for 10 years.
It's like any insurance policy - you pay in, you are a member and it should be there for you to access it if you need it and invariably if you need one part, as in unemployment benefit or illness benefit, then there are other benefits that kick in, rent allowance, access to education (mature student), medical card etc.
It's not supposed to "give you back" what you put in.
Pretty much every country with a social insurance system has a strong pay-related component so there is a link between what you pay in and the benefits you expect to receive. Either contributions are capped or benefits are increased (or a combination) - why should Ireland be so different?