I don't think we will necessarily return to the '2019 way of living' on 21st June, as I think testing may be required for large scale events (festivals, sports stadiums etc), particularly for those who are not vaccinated, however I'd be surprised if that caused more uproar as it seems fair enough in my opinion.People in the UK believing that on 21st June, or the equivalent in whatever region you're in, we magically go back to 2019 way of life are going to be sorely disappointed I think. Just a head's up now
It was always going to be gradual easing. Even after the current announced tiers (when haven't there been some form of tiers during this crisis?)
I am very confident that the rest of the restrictions will fall away. Summer 2020 we reached the point of 20th June, as in everything was up to the point of 21st June changes. If vast majority of the UK population has been offered a vaccine, including 2nd doses for all at risk groups, then I don't see any risk around that 21st June reopening.
International travel is a different beast unfortunately and is more problematic to sort out, but I see nightclubs, festivals etc all starting up again from 21st June (perhaps subject to a negative test or vaccine).