Yes but it's WAY more marginal than nonstop vs.1-stop

I'll pay a little more to go BA via LHR vs. LH/KLM via FRA/AMS but paying more than the non-stop from LHR which is already at a higher price (because it is non-stop) tips the balance in favour of LH/KLM.

If you already have to put up with a stop then a shorter total journey time of an hour or two does not justify double the fare. If the (ex-region) fares were closer to the competition then BA has the opportunity to leverage the better schedule - at the moment they are pricing themselves out of the market in many cases as ex-region they lose the added value of the non-stop flight but still charge for it.