Re: It was....
From what I've read, "Bomber" Harris does seem to have been both resistant to change and overly obsessed with the theory that "strategic bombing" of industrial and political targets (read: cities filled with civilians) would bring Germany to it's knees, despite the fact that Germany had tried the exact same technique on the UK with very limited success.
"The Lancaster bankrupted Britain; you could say it was one of the factors in why Germany is now #1 country in Europe."
Really? I found some numbers (http://www.lancaster-archive.com/lanc_sortie_cost.htm) which are a bit odd ("5000 tons of aluminium" per plane sounds a tad dodgy, for starters!), but assuming the headline figures are accurate, it cost approx. £42,000 to buy a Lancaster and £13,000 to send it out for a sortie. Or approx. £1.9 million and £580,000 in 2018 prices.
Wikipedia then states that approx.7400 Lancs were built, and flew 156,000 sorties.
Using some basic beer-mat calculations, and assuming that a "sortie" is equivalent to one plane, the manufacturing costs were approx. £15,000 million and the overall running costs work out at about 90,500 million - or around 105 US billion in total
Finally, https://caseagainstbush.blogspot.com/2005/04/financial-cost-of-world-war-ii1u.html states that WW2 cost the UK the equivalent of £1,260,500,000,000 in 2005. Which works out at about £1,830,000,000,000 in 2018.
So, while the Lancaster bombing sorties were expensive, they were only around half a percent of the total UK war cost.
The above doesn't take into account secondary costs, such as the training and salary costs for the crew and engineers, but I think it's fairly safe to say that if the Lancaster hadn't existed, those people would have been put to work elsewhere in the war effort (i.e. they'd still require training and paying), so it's somewhat moot in this context.