I don't think people like having multiple computers, and since they need portability, they want a beefy laptop. I personally hate spending time on all the incidental configuration that having multiple computers entails; keeping them up to date, making sure that all your settings are sync'd, and the inevitable configuration that isn't in easily git-able config files that you have to perform manually each time.
I also find it to be a pain in the ass to unplug and plug laptops in to docking stations; you get up for a meeting, none of your windows are where you left them when you get back. So I just use an iPad and ssh to where I need to work. This doesn't work for everyone, but since I mostly only use a web browser and a tmux session, it works fine for me. And thus, I don't have to deal with configuring multiple computers or carrying around a heavy laptop. Great when you travel; it's hard to say "no computer this trip!" and the iPad fills the gap nicely. If you are travelling for work, there will be a computer with an ssh client on it for you when you arrive. If you are travelling for fun, you probably don't want to spend a ton of time on the computer, but it's nice to be able to watch a movie in your hotel room or peruse an ebook before bed. So I just have a very powerful workstation and a very underpowered non-laptop, and get what I think the best of both worlds is.
But many people really like having the same setup at home, at work, and when travelling, and for those people, the beefy laptop seems like the right solution. (They probably also use programs that were developed after 1980, and need the GUI anyway. I think I would be stuck if I needed to use Fusion 360 or lay out a PCB while out and about with my iPad. But it's never come up for me.)
(My experience is based on my 2015 Macbook that I had at work. It didn't have a docking station, so every meeting that you took it to involved unplugging at least 4 cables; power, USB hub, 2 monitors. OS X appeared to be worse than Linux at handling displays going away, so it was always a major undertaking for something that should not be a major undertaking. I'm not really a Mac person, though, so maybe I was doing it wrong.
My personal laptop was a Surface Pro. I never used it except when travelling, so whenever I arrived at my destination it would turn on and say "hey you haven't updated me for like 3 months, this is a major crisis and I am going to freak out until updates are installed. This requires 1TB of data and 12 hours. Have fun! Oh by the way, all your settings are gone now and if you change them, I will also change them for you on your desktop at home when you log back in! Fun stuff! Value add! Innovation!"
No more.)