It depends what you're doing as to whether the CPU is enough, but RAM is still a frequently-cited constraint in the laptop world. Obviously with the immense rise in popularity of laptops, mobile CPUs are now 'fast enough' and have been for a while, but when you do need the grunt, desktops are nice. I imagine most developers these days have 'forgotten' how nicely desktops perform, simply due to lack of access.

My own anecdata: I work in two places, one where I have a 'nice' laptop (some old-but-beefy Alienware thing) and one where I have a 'nice' whitebox desktop. When I'm on the desktop, I find that I'm not keeping my computer's limitations in mind as I do my work, whereas on the laptop I do. It's not at the forefront of my mind, but it's there to some degree. Before I moved to the Alienware (16G ram), I was on an 8G laptop, and I had daily issues with that constraint - even though all I used daily were terminals, about 15-20 browser tabs[1], and maybe a screencap program.

Then I go home and play games, and in that realm, laptops really are the middle-child if the game has any GPU or CPU heft (though again, laptops have the benefit of portability).

[1] not all website are created equal, of course...