This makes me reflect on prior milestones in PC packaging from my own POV. There is an almost tidal dance between the various thermal and performance measures and how these different devices meet use cases. But I think there is also the overall flattening trend where machines have exceeded "good enough" for many people and so the differences are more subtle, highlighting thinks like expansion/upgrade/maintenance versus aesthetics or other intangibles.
A long-term shift for me is that my storage needs stopped growing with the market. Decades ago, I needed to run multiple HDDs whether for mass storage or RAID protection, but now find myself satisfied with mostly single-SSD systems. For personal use, I can mirror and backup between systems rather than needing so much redundancy inside of one. And, any machine I would consider today has sufficient desktop graphics to drive one or two 4K displays to my satisfaction for reading, writing, web browsing, and general software development. The most relevant specs for me now are CPU+GPU+RAM vs power consumption, noise, and heat.
You might think the NUC was aimed right at me. But, I ignored NUCs as I saw them as just another bookshelf system which I'd already dismissed before Intel entered the game. For an integrated black box, laptops seem close enough to the same specs, while arguably having more versatility and better pricing due to their market size and economy of scale. But let me go back through my long-term observations here...
A little over 20 years ago, the Pentium-M made a showing that seemed to bring laptop performance up to meet desktops, largely because it was so much more power efficient and didn't suffer as much thermal throttling while competing against the hot-running Pentium 4. For a brief period, I thought all I needed was a Thinkpad. I also fantasized about a desktop based on one (or more!) of these chips. Years before that, the Pentium MMX made a similar showing in laptops, but then desktops got into SMP and bigger RAM and the MHz wars.
Around the same time as the Pentium-M, mini PCs like the Shuttle XPC gained popularity as a format between normal desktops and laptops. They usually used desktop chips and heat-pipe cooling solutions, with some limited expansion bays for disks and PCI cards. But the Athlon64 soon arrived and upset the status quo. I was enamored with an XPC running an Athlon64. I later soured on this XPC form factor when I realized it was almost as disposable as a laptop. Few parts would complement the exact model I owned, and most useful upgrades meant a whole system replacement. I learned that motherboards, power supplies, and cooling solutions also need maintenance or upgrade options.
I reverted to uATX boards and chassis for home systems. I could manage these as Ships of Theseus with more modular upgrades over a decade or more, including a system that migrated from Athlon64 to Athlon64 x2 to Phenom. Also following on the Pentium-M was Intel's response to the Athlon64---the Core and Core2 eras. I left AMD behind and enjoyed long-lived Core 2 systems starting starting with the venerable Q6600 and visting Haswell to end with Skylake. I still have the Skylake system in cold storage, because I've found myself back just running laptops.
On my employer's budget, I always went with beefy Intel-based workstations in the office and Thinkpads for travel and after hours or occasional WfH duty. My home systems were mostly for entertainment. The Covid lockdown sent me back into using a work laptop full-time, as we scurried to full WfH. My first Ryzen-based Thinkpad was eye opening as a capable desktop when docked. I eventually retired the workstation in my (now vacant) office, as I wasn't even bothering to access it anymore. Other work things continue on remote access colo servers and cloud hosting...