Same for my SFF PC which only came with 2.5g onboard and no extra slots because ITX and can now do 10g via the same USB adapter which is great.
I agree, but laptops are severely power and storage limited. How many >100GB games or whatever can you really download and actually play on a typical laptop? If faster Ethernet increases power consumption, it's probably a negative overall.
For the niche enthusiast, that dongle is fine.
And yes, some of those links are above 1gbps so that the users can have individual 1gbps links.