Totally agree, visited Brittany on many occasions from Plymouth. On paper Dover to Calais seems cheap until you factor in fuel used and valuable holiday time lost getting to Brittany. I think that a lot of people don't realize how big france is compared to the UK.
I think you will find that Tezza33 did the maths on this on page 3 of this thread, and the conclusion was that it is never cheaper to go Plymouth/ Poole to anywhere in France. By my own experience is that for us to get down to Poitou-Charentes we save about £200 going Dover - Calais, or as we tend to do more recently Newhaven - Dieppe. Holiday time lost, yes I can agree with that, but we never use the toll roads, even when we are in rush, so the journey becomes part of the holiday. However the stretch Calais/ Dieppe to Rouen does become a little tedious at times, certainly after the 20th or so time you have done it. I personally am certainly aware how big France is (just come back from a 2000Km trip in 5 days doing a bit of furniture shifting) but if you think France is big, you should try Australia - 2 days solid driving Sydney to the other side of Brisbane, you are then faced with a big motorway (think dual-carriageway) sign that reads 'Cairns 1766Km's', now that's a big country. I treat driving in France or Europe generally much the same way as driving over in Oz, you just keep trundling along, take a break or two on the way and just enjoy it. Unlike the nutter that I met in the South of France last year when we were on our way touring some of Spain for 5 weeks. His advice was 'from here set your cruise control to 75mph, no need to stop, and you will be in Benidorm in 6 hours'. I hope he enjoyed 'seeing' Spain.
Getting back on thread, we have never experienced any problems in 40+ years of touring France. The only problem we encounter more recently is the aries filling quickly, (we have never been on a French campsite) particularly in the Summer months, just too many campers these days, mostly French of course. French austerity, I don't think so.