Both DQVIII and IX sold more in EMEAA than in the Americas:
Pokemon was massive here in Europe as well.
It's generally a vicious cycle with JRPGs in Europe, games don't get released, so people guess there isn't a market for them, leading to less being released. This cycle is less true now, due to the successes of games like FFVII and Pokemon.
For example, during the 16bit era, Europe didn't get any of these SNES RPGS:
Final Fantasies IV - VI
Dragon Quest V and VI
All Fire Emblems
Ogre Battle MotBQ
Seiken Densetsu 3
Super Mario RPG
Tales of Phantasia
During the 5th gen, things got a little bit better, however Europe still missed out on:
Tactics Ogre port
Chrono Trigger port
Tales of Phantasia port
Tales of Destiny
Tales of Eternia
Dragon Quest VII
All Arc the Lad
Ogre Battle 64
By the 6th and 7th gens, Europe gets most RPGs that are localised to the US, however last gen we still didn't get these:
Baten Kaitos Origins
Tales of the Abyss
Tales of Destiny remake
Some of the Xenosaga games
I'm not sure why the text got smaller and smaller, but...
Maybe the issue is brand recognition. If the brand is well-known (or well-advertised, you should know how many adverts there were here in the UK for DQIX...), then it'll sell well. However, unestablished brands and new ventures into the market find either short term success, like Tri, or none at all.
Golden Sun has already been mentioned, but what about, say, Tri? Have you seen this week's sales?
Now, that may not look too bad, but go back only a couple weeks, and look at the sales, only 970 one week, and I believe 1 week not too long ago it didn't even reach 10 sales in EMEAA!
So this lack of long-term support is no doubt dettering developers and publishers alike, hence the lack of these games and other ones you mentioned in the UK. Which is sad