Certainly around where I lived in the UK, near Birmingham, there has been a huge drop in E6 processing, and I know that's the same in London & elsewhere.
My local UK lab stopped E6 processing at least 7 or 8 years ago it was farmed out to another large lab, that 2nd lab in turn cut processing to 3 days a week. Professional use of film has slumped not just E6, first it was Kodachrome then E6 & C41. The wedding photographers are still one of the largest professional sectors using film.
I think if you looked around most cities in the world you'd find an enormous difference in the number of labs and the turnaround times compared to 10 or 12 years ago.
That doesn't mean you still can't get a fast turnaround on E6, most large cities had a reasonable number of labs offering the service but that number has dropped, many labs say they offer the service & farm the work out, if your lucky and the lab you chooose has a good clientèle of commercial photographers regularly shooting E6 then they can afford to offer a 2 hour turnaround, but it's no longer the norm.
I disagree. When it comes to making prints, shooting digital with a good DSLR does a damn good job. But digital CAN'T give you a transparency! The way I see it, film has the best chance of surviving by doing what digital can't do rather than trying to beat it at its own game.
I shoot both film & the other commercially I have no choice, but I much prefer film - B&W and Colour for my own work and a few select commercial assignments, so a C41 equivalent of Kodachrome is potentially idea.
Ian