Even Boris seems to realise that! If the travel industry is to survive at all, it needs certainty. People will not book a foreign holiday if they fear a quarantine imposition just before they leave or whilst they are away. I am all for people doing their own risk assessment and if they want to go, then they should, with tests enforced on return from countries with a high prevalence, but no quarantine.
Covid will always be with us. There will still be cases next year, and the year after, for the forseeable future, with variants rising and falling, that is what viruses do. We are offered good protection from serious illness with the vaccines. If you haven't seen your family for a year and a half, weigh it up. Will you take the very slight risk of a week or two in bed in order to see them?