I am happy to say that my desktop from 2004 is still alive and kicking. Some websites are a drag, but some on-board replacements have kept the old warrior running. I hope one day we can keep our smartphones on life support for a long time.
Basically, I now use laptops for games and the desktop for storage/office tasks. The single board desktops are quickly growing out of the RPi-type niche and look increasingly competitive with the traditional ATX platform for this role, and opting for them means that I define my system around the storage and RAM, rather than the multitude of PSU/motherboard/CPU/GPU/case combinations, which is both easier for me and eliminates most instances where components push each other out of their tolerance range. So long as I'm on the same memory and storage, I can replace everything else in the case for <$200. This is really what sold me on the idea; since my existing system fell out of warranty after one year, repair would be the cost of a new board. But if the whole system is the board, then a failure is a forced upgrade.
My laptop is always ssh-ed (mosh provides the "always" aspect) into one of the others anyway. It's stuck with 8GB of RAM which is often a bottleneck, especially since Docker holds onto a couple gigs and Chrome tries its hardest to get the rest. Portability is necessary but not sufficient to addrrss my computing needs.
If I could, I'd have a 4x8 foot display with no decrease in pixel density. I.e. an incredible number of pixels.
Heck, why stop there. Give me a wall sized display! Phooey on laptops.
I have my MacBook Pro hooked up to a 4k external display, Microsoft Natural Keyboard (or whatever they are called today), and a nice big Magic Trackpad 2. I can undock it and have exactly the same system on the go. the MacBook Pro can drive multiple screens (2x4k on 13", 4x4k on 15"). You also use an external GPU over Thunderbolt 3.
What's the point of having a laptop if you can only use it with an external monitor, keyboard, and mouse? A powerful desktop is much cheaper, and you can stuff huge disk drives in it.
When I'm on the go, I bring a cheap laptop (in case of loss, theft, or damage) that doesn't have my whole life on it and mainly take a vacation from working. (And I'll use the time to catch up on my professional reading.)
Really hard to get myself to code on my laptop now.
i think you would find this setup to be really poor.
you need be within ~2ft viewing to appreciate the difference between 1080p and 4k at 24" diagonal display size.
sitting 2ft from an 8ft wide display will give you very poor viewing angles for the majority of the content. at greater distances than 2ft, the pixel density of a 4k 24" display become nothing more than waste of gpu, cpu and electricity.
As for discerning pixels, I know that the retina display is distinctly easier to read than non-retina (both from Apple) even though I could not see the pixelation on the latter. Watching video does not make much difference, but reading text sure does.