Complain all you want about the U.K. singles chart - it's pretty much the only country where CD singles still sell quite well! In fact, plenty of artists can get sales in the tens to hundreds of thousands. This may pale in comparison to years ago, but it's tons compared to every other country, including the U.S. This is why U2 - and many other artists - no longer have CD singles for sale in the U.S. They simply don't sell (or sell well enough to compensate for the expense).
Personally, I think for highly anticipated artists - like U2 - at least the first single should come out in the U.S. But perhaps the era of the CD single is at an end. The 45 rpm vinyl single can still be found here and there (mostly for old jukeboxes and collectors), but with the success of iTunes and similar sites, I don't think we'll have CD singles for long.
Which reminds me... Now that Eminem has an iTunes/iPod commercial, what do y'all think of that? Has he "sold out"?