"I assume those high risk (like my other grandparents) will be shielding so I don't think about passing it on and before COVID when did people really think about passing stuff onto other strangers"
We are really fucked if this is most people's attitude.
We currently have low levels of covid. We have a chance of keeping levels low, but it depends on people giving some thought to whether they might be passing it on and taking steps to avoid it.
This is a nationwide infection control problem and if millions of people aren't bothering to try to stop the virus spreading then cases will go straight back up.
It's not even that hard. There are loads of things that most people can do, most of the time, like handwashing, only meeting outdoors, not mixing if someone in the family has any symptoms at all, trying to stay a few feet apart from strangers especially in enclosed spaces.
People who don't bother to do these things because they're not personally scared of the virus put us all at risk of cases going up fast again. And then hospitals will be restricted for longer, schools won't be able to open, all the worst bits of dealing with lots of cases will be back.
Lots of people didn't bother thinking about passing things on before lockdown but that wasn't ok, it was shit (literally in the case if norovirus outbreaks that could have been avoided by people taking sensible precautions).
Children who need to be at school, cancer patients who need treatment, people like me waiting for postponed non-covid treatment - we really really need infection rates to stay low, to get even lower, and not to rise again. We need people to keep caring about not spreading the virus. The worst possible thing for us is people deciding that they don't care about catching and spreading covid because their individual risk is low.
People who think it doesn't matter any more and no precautions are needed - please reconsider that. If covid rates rise again because people have stopped bothering to be careful, don't think it's just elderly or vulnerable people who will suffer and who could stay at home to avoid it. It's far far more people than just those.