And Spain locked people in their homes to the point where there was a black market in borrowing other people's dogs in order to have a legal reason to go outside, and did worse. There is not an obvious relationship between severity of lockdowns and deaths or hospitalizations. You see this in the US too, where the media have been demonizing Florida for months for its relatively lax restrictions, while its death rate is right at the national average.
Also I think it was never practically feasible to isolate vulnerable people as you describe.
And it is practical to expect the entire population to put their lives on hold for a year because of a disease that is not a significant danger to most of them?
I just hope the vaccines achieve immunity and stop this pandemic. This is great news. Too bad it's not approved in the EU yet. Hopefully early next year.
Also, I think you are missing the point. The swedish strategy was based on people following the recommendations over a long period of time. Locking down is not a sustainable strategy, especially when you believe that the pandemic might last for several years.