My 4 month old laptop has hdmi on the back, ethernet on the left, four usb 3.whatever slots with two on each side, two USB c slots on the right side, and a microsd slot.
I think it even has a 3.5mm headset jack but I’d have to get out of bed to check. I don’t have any peripherals that use 3.5mm anymore though so it’s just a nice little bonus.
Yes, someone would have. Eventually.
But valve did it early.
It’s easy to fill a niche once it’s formed. Not so easy to do before, or as it’s forming. Or predict if one will form.
I’m not saying valve or Gabe had some kind of foresight or wisdom, I still think it was a gamble. It just happens to be a gamble that worked.