Gaming laptops still have decent expandability, can't speak for quality as I've only had this one for a little under 1.5 years, but it has enough ports and upgradable RAM/SSD.
Laptop connectivity?
VGA? Long gone.
Serial and parallel? Even longer gone.
PS/2? What's that?
Line in, line out, mic? Condensed into two, then one port than nothing.
Express Card/PCMCIA? Once upon a time...
Ethernet? Becoming Rare
Now they are removing USB ports!?
This is all !!
But I don't expect the Steam Deck to offer more wired connectivity.
Gaming laptops usually have really stupid failure modes, like the flimsiest screen failing either at the panel cracking, or the hinge cracking, or improper MOSFET protection causing them to short after a few months or few years, improper cooling system, and peripherals not being "gaming-tier" besides the CPU and GPU (so, slow RAM, bad keyboard (RGB doesn't count), slow touchpad, etc.).