"Apparently Windows 7 will help things along" - well, given how they enforced Vista on notebooks(sans business oriented models which shipped with downgrade options) it might just happen again with 7. Windows 7 is neither broken nor immature as Vista was back when it was released (but not now, mind you), and it's obvious that after some time we'll get it on laptops.
On the other hand, the notebook market will grow and that is obvious for a number of reasons. First of all, the devices are getting cheaper. Second, an average user is intended to use his/her notebook for two-three years and then move on to another one and while in developing countries such an idea is still in its infancy as laptops are still considered a luxurious item there, it works fine in the UK or USA or Asia. This coupled with the inability to substantially upgrade hardware will cause many to switch their notebooks for newer models after several years, again and again.
Third, netbooks wont' kill the ordinary laptops. They're bound to hit the wall with miniaturization - several inches less in terms of screen size and we're home with for example iPAQ 210(EUR version 214), and your eyes are not going to last long against all of those super-tiny icons, texts and GUI. Performance-wise these devices are (at least for now) banned to the realm of lightweight internet browsking and some basic MS Office work. And many,many people need and will need PDRs (portable desktop replacements) with all the ports, multibays and you name it, as well as lighter standard size (15,4-17") notebooks. Miniaturization is fine as long as it's practical and economical. UMPC anyone?
So the general synthesis is that an ordinary laptop will last and its user base will grow. The same is true for sales figures. We don't need any company to tell us this...or do we?
Peace

Can someone explain why "Windows 7 making people want to replace their notebooks" ?

As far as I can determin, Windows7 performs better than both Vista and WindowsXP on any given hardware, and definitely functions well on machines that simply will not run Vista.

Windows7 is most likely to make me want KEEP my notebook and get a few more years life out of it, not trash it!

The MS centric computer universe has never really seen a "performance release" and maybe this has people confused. But as far as I can see, the quoted statement is completely at odds with reality.

Dweeb

prefer to call it the Kai Ching.