I would imagine so much of the EU market (for family sedans) is full up with European manufacturers, mostly German (including Opel/Vauxhall). I would also hazard a guess that the car market trends here are very different. For example, the Vauxhall Zafira and Citreon Picasso (and other bubbly people carriers like them) are everywhere. So too are the odd, crossover, sporty, but not actually sporty SUV things like the Juke. Seems every manufacturer's having a go at their equivalent and people seem to lap them up. The family sedans don't appear to be sold in the same numbers compared to 15-20 years ago and with steeper competition from European manufacturers, it's probably just not worth their while. I.e. they're picking their battles wisely and focussing on styles of car they know they can sell easily.
Whenever I visit Japan though, I'm always blown away by the cars there. Family sedans are more common, but what I really love and what you see everywhere are the boxy family cars that I would love to see over here, but I don't think the UK market would appreciate of
get them, if you know what I mean. They're typically seven seaters, although almost never used to capacity. The unused seats fold down or just provide extra lounging space for passengers. Seems everyone from Honda to Daihatsu have their own take on these awesome boxy things (think Nissan Cube or Honda Shuttle only way cooler and available in all sorts of various shapes and sizes). Plus, they seem to be made on a base platform and offered with all sorts of interesting variations. There are flatbed versions (some are tippers, others are not), mini flatbed versions with a cabin that'll seat 5, 5-seaters with a wide opening rear specifically for people with wheelchairs, 4-WD versions for people who live in the country side, van versions (cabin in empty shell as opposed seating area) and so on. There's also a crazy modding scene for them. You see bonkers, lowered, pimped out square boxes on wheels everywhere. It's so cool!
I swear, if the UK had the Japanese car scene and range of models, the general happiness and quality of life would so much better!