> I'm not proposing that we should optimise for life years saved, but I do think that the death of a 86 year old is less tragic than that of a 38 year old, and that we perhaps shouldn't evaluate lockdown vs no lockdown purely based on the percentage of the population which died.

I of course agree with that. Just stating lives lost in isolation is misleading. It simply much easier to use for back-of-envelope math, and generally back of the envelope math indicating a course of action would lead to millions of excess deaths is enough to conclude that probably it won't be a great idea.

> which indicates that on average those people would probably live <10 years

This is plausible, but it may not be much less than 10 years either. The life expectancy of someone who reaches average UK life expectancy is close to another 10 years. And we'd probably both prefer neither ourselves nor any elderly relatives or friends to suffocate 10 years before their or our time.

> There have been a significant amount of excess deaths that are not attributable to COVID [2].

So this sounds initially plausible (lockdown stress/economic hardship leading to an increase in suicides) but I believe it's bullshit and that these deaths are in fact due to covid. Since we were talking about the UK, let's go back to look at that: the baseline figure of suicides is pretty low (~6k in the UK for 2019, which is 1e-4 per individual per year). The number of excess deaths in 2020 is at least 12 times higher than that. So the suicide rate would have had to at least double to account for a significant part of that. And nationwide suicide rates are quite stable, year-on-year, including, crucially, during times of severe economic hardship.