Probably, and I haven't experienced lockdown in the UK, but in the US and Norway, even people being quite careful see more than just their immediate household.
It's been pretty loose in the UK. Even during the strictest lockdown, which only lasted a couple of weeks, you could still go out for exercise, go to shops for "essentials" (the definition was liberal). People went to exercise and just happened to be walking 2 metres away and in the same direction as their friends. Hardly house arrest.
In some places. But at any given time many people lived in relative isolations, i.e. Winters alone with family, while in most times no one could have been in a high enough density where you didn't know everyone. So this normal is imaginary while lockdown is like a normal lifestyle even if it wasn't the only lifestyle at all times.
I guarantee you that most people back then would've been hunting, farming, building huts or rearing children. There is no model of the past where this level of isolation was even maintainable. People simply depend on each other to live.
All that changed is that we've outsourced that direct dependence with indirect dependencies, like supermarkets.
Just before the crisis I was watching a documentary on a tribe of herdsmen that come together once a year to find mates.. They have probably been doing that longer than Rome has existed. The idea that the modern world is very much like our environment during our evolution is delusional. An effect of being joined to the western Europeans for colonized people was significant deaths from diseases that can only exist in abnormal densities of people.
My position is AFAICT the same in the entire thread. There is nothing "obviously" wrong and harmful with a lifestyle because it looks different than a modern lifestyle (that is not the result of tuning for positive mental health, but a lot of game theory toward the opposite) and that not everyone leads even today. Tribe size averages don't mean every family everywhere was connected with people outside their immediate family more often than required to reproduce. Plenty of herders still spend most of their time in their atomic family in Turkik places, Africa, etc and have done so since before agriculture. Are they all obviously mentally ill because they don't go to supermarkets?
(To me this is the same observation as that many people first experience schizophrenia at the stage when they are most likely going off to school, the school environment is a change and not obviously more defective for our mental health, those who have crisis might have unhealthy family relationships before hand, etc, etc.)