Somewhere in my "library" I have/had a report (? by a Mr. Worcester ?), possibly for BEA or Vickers, "proving" that the new-fangled jets, such as the Caravelle, could never be profitable, specially on short routes where their higher speed, making (perhaps) more rotations per day possible, could not earn more than a slower turbo-prop. To make sure, he calculated that the turbo-prop's passenger capacity also needed to be a bit higher than that of the French product.
It all looked fine in this analysis, and BEA duly ordered the Vanguard but passengers were more impressed by flying in a jet (quieter cabin ?) and the (not much) shorter flight times, at least on British internal routes. London - Nice was another matter, of course.
Not long afterwards, BEA reckoned that those routes couldn't be economical anyway, at least south of Scotland, I think, as rail would be faster.
As an afterthought, I always thought that the EAS "fleet", static at Perpignan, would have been ideal as a Shackleton replacement, but Coastal Command sooooo badly wanted jets like the big boys ...