I've just waded through most of what has been written and I think it can be summarised as:-

 - The Spanish authorities require you to swap your license for a Spanish one if you're resident here. That doesn't seem to be too unreasonable. But,

 - The EU law, which trumps all national laws, says that you don't have to if you don't want to.

I can think of several reasons, apart from the cost and the time involved, as to why someone wouldn't want to go to the trouble of changing licenses. Particularly if their residency may not be very long-term and they would have to go to the cost and fuss of changing it all back again. On the other hand the Guardia Civil and the, much less informed, Spanish police probably don't understand the nuances of conflicting EU/Spanish law...so you'll probably get fined and have to argue about it afterwards.

In short, you have the choice. is there anything I've missed?

I think tteed too seems to have made a few 'historical bloomers.' The 'looney left,' as the rabidly right-wing Daily Mail used to call anyone who wasn't a Conservative, did not bemoan the sinking of the Belgrano after people were watching nightly the sinking of the Belgrano and the Sir Galahad. The Belgrano was sunk first. The left of the Labour Party did criticise Thatcher for this as she broke the rules of engagement that she personally had set just a few days beforehand.

That Thatcher went, before the Falklands war, from being the most unpopular PM since records began to winning the 1983 election was nothing to do with the economy. Unemployment was still sky high by contemporary standards, as was inflation. That the opposition were divided probably helped her too, but pre-Falklands there were already moves within her own party to dump her before the next election. Her post-Falklands surge in popularity put an end to that.

I think you'll find that my argument about 'minority' languages dissappearing naturally (in the 21st century) can be applied to the example you give of the French trying to stop the encroachment of english.....french quickly being a minority language since having lost its place as the language of diplomacy, a throwback to Napoleanic times, and becoming no more than a one nation language within Europe at least. Returning to the original thread, however, of course we can force our children to reluctantly be educated in a minority language......but are we doing them any favours? And the Catalan issue is that they don't want to give any sensible options....and the language is most-definitely one of the banners of a somewhat-misguided and dangerous nationalism. Most Catalans don't have a clue about their own regional history and, unlike, say, Wales or Scotland with histories going back a couple of thousand years at least, any claim that a 'nation' of Cataluña exists seems to be based on the language (arguably a dialect) rather than the ping-pong ownership of the Principality of Cataluña over the last few hundred years.

One of the reasons that minority languages don't die out is because of the actions of nationalist groups to artificially keep them alive. Whilst I certainly don't condone the forced integration of minorities into a greater national entity and the extinction of their regional identities (as the English did with the Welsh and Franco tried to do with the Catalans and others) nor do I support the idea of small nationalist groups trying to rally political support around the flag of a regional language. Both are completely against the natural development of language. Language is not a static thing and the speed of change increases in a more globalised world. My comment that without artificial support minority languages would most die out within a few decades is a prediction based on the rate of change in the 21st century. Welsh is a perfect example of something that would now be extinct were it not for Welsh nationalism's efforts to keep it going. But to think that artificially keeping alive a minority language has a use other than to bolster nationalist groups is a bit naive. No one would seriously argue that people in a certain region should confine their language to the secondary minority one - what would, say, Wales be like if the people only spoke and understood Welsh? (Think 'Albania!') Being realist the future of language has no real place for secondary regional languages. The whole point of language is to communicate and now we communicate with the world, not just the people in our village. The evidence? How many pages on the Internet are in Welsh/Catalan/Albanian?!