I’ve seen Ultrabook market penetration estimates that range from 40% by end of 2012 all the way across to this, the lowest forecast so far. 13% by end of 2012.
As we all know by now, the Ultrabook is radically different to traditional notebooks in terms of design and production so as far as I’m concerned, if we see all major manufacturers on board with production lines and supply-chains responding, there will be no turning back and the Ultrabook design and production methods will permeate most of the laptop market. I expect we will see the first signs that the Ultrabook design is succeeding in late 2012 with netbooks, Windows 8 ‘Ultraslates’ and perhaps a new style of MacBook Pro looking distinctly ‘new-wave’ and as the Ultrabook design starts to become cheaper because of volumes, the market will flip completely.
By the end of 2013 Intel could find it impossible to retain any sort of Ultrabook definition because most notebooks will offer similar style, always-on and SSD characteristics. [Unless Intel have a bunch of patents tucked away with the Ultrabook trademark!]
You could even argue that ARM-based notebooks running Windows 8 in 2014 could count towards a loose Ultrabook definition. They will certainly look like Ultrabooks. [Again, unless Intel is building a patent barrier.]
The iSuppli estimate of 45% by 2015 is too low in my opinion but really it’s up to Intel and their definition of an Ultrabook, which could change at any minute.