Not sure what you mean about limited expandability, the Macbook Pro has the highest performance I/O of any laptop in the world. It has the most thunderbolt ports (4), the fastest ssd in any laptop, etc. I routinely have mine hooked up to an eGPU, 40gbps thunderbolt adapter, 10gbe, external SSD array, docking stations, etc - all at full speed. No PC laptop on earth can do that.
You have an M1 chip working with an external GPU? Then magically added two more thunderbolt ports. You are special.
I think you need to actually read the thread, or even the bit I quoted at you. The M1 has limited expandability. and does not have egpu support.
The intel macs are more typical in port allocation, but are usually a generation behind in the CPU they decide to put in because apple. Which was my complaint about teir intel machines.
Not to mention that there is in fact at least one windows laptop with NVME pcie4.0 support and with 40GBs thunderbolt. given the way windows laptops work, that pretty much means there is more than one. NVME 4.0 goes well beyond the speeds the 16 inch MBP gets from the SSD in it which seems to top out at 2.8 gig rather than the 5 gig nvme 4.0 hits.
Which leads to one of the bigger problems. Which is that for desktops, in apple land, the future looks like mobile SOCs on the desktop, and the windows desktop realm does all those things and more while having a much larger price differential than laptop to laptop. A laptop with docking station and other perioferals so it can dock and play at being a desktop is more expensive than a desktop, be it apple or wintel. Adding the apple tax to that and the periferals makes it a non starter for a huge swath of the market.
There's a reason why a lot of enthusiastic reviews of the M1 offerings are basically saying it's cool, but I'll wait for the next revision. The next revision, unless they fail to cover their entire line up with it, will reveal if Apple is going to make a more worthy SOC for desktop.