Why are there no new 17inch MacBook Pro available?

Because Apple does not make them.

No one knows why Apple discontinued the 17". There were probably several factors, one of which they may not have sold as well as Apple hoped for. Therefore not justifying the continued cost of making them. These days 17+" laptops are getting scarce even on the PC side. I'd be very surprised if they revived the line, smaller and lighter is the main theme these days.

TThey stopped making them 3 years ago.

http://www.zdnet.com/article/why-apple-dumped-the-17-inch-macbook-pro/

sandi lloyd wrote:

Why is Apple not making new MacBook Pros with 17inch screen available? 15inch just doesnt cut it for me...

While there's no official definitive answer, one possible explanation may lie in why the "15inch just doesnt cut it for" you.

If it's a matter of poor vision, then a larger screen with larger stuff on it makes sense. But if it's screen real-estate, the standard resolution of a Retina display can be increased substantially in the Displays Preferences panel so that all the stuff that would fit on a 17" screen would fit on the Retina's 15" screen too, just smaller. And there is third party software (e.g., Eye-Friendly in the App Store) which can increase the effective resolution even further, if your eyes are up to it.