Why do movies and TV shows still have 555 telephone numbers?

Every time a character uses those 3 fake digits, it destroys the illusion. Why not set up a working number? There are plenty of companies that offer independent voicemail lines for less than 10 bucks a month.
It’s a chance to make the story a bit richer. You don’t even have to do a full blown alternate reality game like LOST. (But you should.)
Even the publishing world gets it.
Check out the latest issues of Time Out New York:

That’s dating columnist, Julia Allison on the cover. And her article, How to make You(tm) the sexiest brand on the market, contains this paragraph:
This is self-marketing. And every single person should do it.
People get marketing all wrong. They think it’s all about trying to be what other people want. But it’s really about being brave enough to put yourself out there — who you are — and not change in the face of people trying to make you something you’re not. My detractors will never like me. But honestly? Who cares?

That's good advice for any brand.
If I wasn’t engaged, I might just give her a call.