I am sitting in my van, in Cambrils, reading this....so couldn't resist adding my bit! We are here for three days (ish) before moving south. (By the way it has been raining for the past twelve hours so there's not a lot else to do!)
I think many of us are creatures of habit and, of course, it wasn't so long ago that the Lyons route (at first via Paris, then later via Reims) was the only all motorway route to Spain. When we were working, and only had two week holidays, it was necessary to get there quickly and then the only other reasonably quick non motorway route was straight down the N20 to Toulouse, then via Narbonne. Maybe some people still follow their habitual route without looking for alternatives.
At the rate that France has been building new roads in more recent years there are, of course many alternatives now, and it really is a matter of choice.
Like Val, I costed various routes this time, because, as she says, the combined cost of fuel and tolls has become very expensive, even since last year with the price increases plus poorer exchange rate. My conclusion was that overall there was little difference in cost between the routes via Clermont Ferrand, Toulouse/Bourg Madame, and even Tours/San Sebastien.
Now we are retired we have plenty of time so it really is a matter of choice and I tend to leave the choice until the last minute, and keep off toll roads where practical, to save cost.
We ended up taking the motorway route via Reims to Troyes (relatively cheap), then cross country to Nevers (Camping Cheques site), then to Clermont Ferrand and down the A75. Not everybody's "cup of tea" but suited us and we didn't pay any tolls between Troyes and Beziers.
To answer Tony's question - if you are still there Tony! - assuming you go via Rouen to Tours, the non motorway route via Alencon and Le Mans to Tours is perfectly good and I would personally take that - but it's a matter of choice.
......wait a minute - its stopped raining - must go and look at the outside world!!
Regards
Keith