I just read an article on the BBC website about the use of the definite article in the name Ukraine/The Ukraine.
It was quite interesting and raised several interesting points. (Although it listed a lot of "the" places that have recently lost the article in common speech.)
One thing that did bug me, though, was a little S-shaped oversight, because they completely missed the point that all explicitly plural proper nouns need "the". "The Netherlands", "The Phillipines", "The Bahamas".
Consider how you would refer to someone by his surname only... for example the western Alias Smith and Jones. Now if you want to use the family name in the plural, you need the definite article, eg. "keeping up with the Joneses".
The argument in the article about the fact that "the Netherlands" is made up of readily-understandable elements doesn't really hold up; there are many English-language placenames in the UK that are made of generic elements but don't take the article, like the multiple places called "Bridgend", places like "Holyhead". The archetype, though, has to be "Land's End". It is the single most meaningful placename in the whole of the archipelago -- it's iconic and valuable because of its meaning is abundantly clear. Yet we do not use the article. We used to, certainly (see the Wikipedia entry for Land's End for evidence). The historical origins are interesting, definitely, and certain classes of placenames do preserve old patterns, but language change is a subtle beast, and sometimes it isn't the form that changes, but the reasons speakers have internally for using that form.
Also, looking at the Bahamas and the Phillipines, it should also be noted that historically we didn't always name island groups in the plural, particularly in Scotland. Conservative natives of Uist, Orkney and Shetland will still refer to their homes as such, whether outsiders are likely to call them the Uists, the Orkneys and the Shetlands. (I would personally be very surprised if the English kings bent on conquering Scotland and Ireland said they wanted complete control of "the Britains" rather than simply "Britain", because this looks like a pretty new feature to me, and I suspect that it may be to do with the borrowing of French and Spanish names for new island groups in colonial times.)
The modern speaker of a modern language has no internal knowledge of the language change -- if a language encoded all its history, languages would be so "big" that they would be impossible to learn. Instead, every generation observes what the generation before says and tries to work out for themselves why they say it.
Now I know someone's going to mention shops and companies as a counter-example, because the supermarket chain is Morrisons, but that's actually a possessive. It's Morrison's supermarket, after all. Heck, when I was a child, I used to append 's to practically every single-word shop name, as did my parents. Tesco's, Bejam's, M&M's, etc. Somehow Comet got an exception, and Fine Fayre was left as-is because it was two words. Oh, and look at that: a two word generic with no definite article -- another disproof of the BBC's claim.
But you're right that Morrisons has no apostrophe these days, and neither does Greggs. This is another example of language change, because as more and more shops drop the apostrophe in order to have their brand match their website domain name (Sainsbury's are a rare case of defiance -- how long that'll last now that the Sainsbury family aren't the main shareholders is anyone's guess), and as we get more exposed to Tesco as the official name rather than Tesco's, the next generation will grow up without the cues that it's a possessive name, and even though I will hear "Greggs" as "Gregg's", they won't -- in fact, it's entirely possible that everyone under 16 already doesn't recognise it as a possessive form... and yet we speak the "same" language.
When that generation reaches their thirties and are editing and delivering our daily news, then things might change, because a generation that is entirely comfortable and happy with S at the end of their proper nouns will happily say "Netherlands" instead of "the Netherlands".