. . . those who shout 'nut we PAID NI all our lives',,,yes, indeed but it is not enough to pay pensions, pay for care homes, hospitals, doctors, and sll the calls on the NHS ...it did not keep up with costs and unexpected longevity. The government actuaries were sadly not making provision for this and all the calls that are on the NHS now .............
I don't think people 'shout' in the rather petulant way you suggest - they may point out that fact, which is not the same thing at all. You are right that there is not enough to cover all the things you mention, but governments have a choice. They could increase taxes and also increase the level of cover. They could introduce a defined NI scheme payable by everyone over 18. They could rejig current spending plans on things like HS2. Or they could carry on letting the NHS that people have paid into wither and die, whilst those who can afford it go private.
Telling people in the rather sneering way you have just done that they have not paid enough, and implying that they have no right to point out that they have made decades of contributions might explain why you have been pilloried. All everyday citizens can do is pay what we are asked for, and it is up to governments to ask for more if they need it, in accordance with their party's philosophy about who should pay most.