The bureaucracy involved in maintaining records on 'contributors' for 40 years or more is expensive and unnecessary – particularly given the level of means testing. NI has long ceased being an insurance – those who pay in most get the least; Jobseekers Allowance expires after just 13 weeks unless you have no money; should you have a full contribution record you get a 'full' old age pension, however if you don't have a full contribution record and have no savings, your pension is made up by income support which gives access to things like housing benefit and one can be better off than someone who has a full contribution record.
Let's be honest and classify it a TAX rather than a REVENUE RECEIPT.
Why is this idea important?
As a tax, the huge computer centre and staff needed to track contributions would cease to be necessary. The need for a separate National Insurance Fund would also fall and we would move back closer to the original idea of the Consolidated Fund where all Govt revenues should be received.
In addition, employers would be able to add their existing NI contributions to the salaries of staff and so truly reflect to employees the cost of Government; get us all to recognise the huge burden of the state.