It's not any one factor, but a combination of things, most of which (travel costs, the way the current range is regarded, etc.) have been voiced here. I do have another point though:
The figures for surviving cars in 2CVGB is a good example of what's happening with our cars. There are only a few hundred Dyanes left in the UK, and the last time I saw any of the Dyane Register data 80% of the survivors were post '78 disk brake cars, mainly because the older cars weren't as developed so weren't in as much demand until they became collectable. When I owned my first 2CV back in the 90's, it was one of only 200 70's drum braked cars known to the club, again because many people had upgraded to later disk braked models in the 80's. Older models would also rust away and be replaced by later ones. Those Dyanes that are out there only survive because of the die hard enthusiasts who didn't want to (in their eyes) compromise by buying a 2CV. There are many more late model 2CV's being rebuilt today than there were Dyanes and Drummers 10 years ago because there's nothing newer to replace it with without buying something completely different.
The same works with BX's - many people replaced their GS's and GSA's with BX's because it was a more developed, more efficient vehicle, leaving just a few diehards keeping their G series cars running. The BX's in turn have been replaced by many owners with Xantias, either because they like having a newer car or because the BX was worn out / rusty / getting difficult to maintain / whatever. As people have mentioned, the C5 is a completely different animal, and to many who like the centralised hydraulic system they don't see a suitable replacement for the Xantia, so are now hanging onto them.
For our size Citroen models, they can be compared to A series Citroens by comparing GS survival rates to those of the Ami (double figures), the BX to the Dyane (low hundreds) and the Xantia with the 2CV (thousands but in decline).
While Citroen's change to more conventional designs may have deprived the CCC with an ongoing enthusiastic ownership, I think at the same time it may do a lot for the survival rates of Xantias and XM's, and hopefully those BX's that are currently left.
Mike Sims
BX 19RD Estate Mk1 - Timex!
BX 4X4 Estate - Oh god, I've done it again!
BX 17RD MK1 - it called to me!
BX14 TGE, - SOLD
XM Turbo SD,GS Club Estate,Visa 17D Leader,HY Pickup,Dyane Nomad,Dyane 6,2CV AZL,Falcon S,Trabant P50,3x Land Rovers (88" series 1,109" series 2a FFR,series 2a Marshall ambulance),DKW F7, Lambretta LD150 x 1.5,Mobylette SP93,Ural Cossack,Ural M63,CZ 250 Sport,Honda Varadero 125,lots of bicycles & tricycles including (but not only) Sunbeams,Higgins & Bates!
I guess we just have to make sure we look after the cars that are left, sort of custodians for later generations to have at least some available
Amen brother, its true though, one day there will be none left and those who want one either cant find one or they are too pricey due to scarcity. Old Fords have gone that way.