It's a curious comparison, to say the least. Britain was completely broke in 1945, and yet years of hardship and struggle meant that the working class were ready to demand change that hadn't seemed so urgent to them when the country was far better able to afford it. Carlaw seems to think voters will react to the current crisis in completely the opposite way by demanding less change at the end of it than they otherwise would have done.
Or perhaps he just means that governments and leaders can seem wildly popular during a crisis, but that things will look very different when an election comes around? That's sometimes true, but if that's what he's getting at, the Attlee comparison is still misconceived. There was polling done during the Second World War that suggested a handsome Labour lead (albeit people didn't take it seriously at the time because political polling was in its infancy). It simply wasn't the case that Churchill was the people's choice in wartime but not in peacetime.
Or perhaps he means there'll be a reappraisal of the Scottish Government's handling of the crisis in the cold light of day? Maybe there will be, but the main criticism that will be levelled is that they remained too much in lockstep a few weeks ago with the herd immunity madness from London. It's hard to see how the Scottish Tories can make much capital out of "you were agreeing with the London Tories too strongly". It's been particularly extraordinary to see Carlaw accusing the SNP of a lack of transparency over care home deaths, given that everyone knows the Conservative government at Westminster is being considerably less transparent on that subject than the Scottish government is.
Carlaw thinks the SNP will "look ridiculous" if they press for independence in the 2021 election in spite of the events of this year, and that doing so could be a recipe for a surprise defeat. That may or may not be true - anyone who claims to know for certain what the long-term effect of current events will be is deluding themselves. But it does seem likely that if the public cease to have patience for politicians pushing for independence in the near future, they'll inevitably react in exactly the same way towards politicians hellbent on the hardest possible Brexit. It may be that what Carlaw has really done is put his finger on the reason why his party should actually be expecting a drubbing next May.