Alternatively, realise that the problems in (b) are largely solved for reasonable OSes where the vendor takes responsibility both for automatically getting you

Alternatively, realise that the problems in (b) are largely solved for reasonable OSes where the vendor takes responsibility both for automatically getting you security patches and for keeping you working without major disruptions. I'm not sure where you've got the idea that updates are all-or-nothing, but some of us have been living a life you seem to think can't exist for decades at this point.