It will depend on the user. Simply put I will not now or ever go to a laptop. I just dont like them. They are too cramped for me and I like my space. My keyboard alone is larger than most laptops, even the 17" ones. So you will be hard pressed to get hard core people to switch to a laptop.
Then there are the extreme customizers. Those that love to be able to upgrade and change parts out when they are available. While it can be done with higher end laptops, it is still far more expensive to do on a laptop than a desktop. Getting a new top of the line laptop that allows you to change video cards is gonna cost you about $1,000. The video card will be about $100 more to get a laptop version than a desktop version. For that same amount of money, you could build a top of line desktop PC which would kick the laptops rear end in all aspects. So these people would be unlikely to switch.
Then there are others that like the ability to have abundant storage. I am also in this category. I have almost 4TB of space in my system now and 80% used up. I am looking to add another 2TB soon. I will be building a server soon to house most of my stuff to get it of my main desktop, but such a method isnt easy to accomplish with a laptop. I could go the NAS route, but then I wouldnt be able to stream my media to my gaming consoles. At least not with the ease that I have now. It doesnt matter the file type, I can play them all and use my PC to transcode them. While if I went the NAS route, I would have to convert the files to 2 different or 3 different formats. 1 for XBOX, 1 for PS3 and 1 to work on the Wii. Making storage even more difficult having to have 3 of every file to be able to be used on the devices I want.
So it only makes sense to just go with a desktop with 6-8 SATA connections to allow me to expand my storage. That way I can just put my digital copies on my HDD, stream them and have them work flawlessly. Instead of having to use software to convert them to a different format to work on various systems.
But not everyone has such demands. My wife made the switch to a laptop and hasnt looked back. The laptop does all that she wants and it is portable for her. So she was able to make the switch, mainly cause I have her connect to my desktop for things that she wants to do when it comes to streaming and storage.