I guess I should have been clearer to point out that's it's still quite possible to(common?) to buy non-type C devices (you can still buy DE-9 serial devices too), but it's certainly possibly to buy a Type C version of almost anything (external drive/card reader/a lamp...).
Everybody's mileage can vary of course.
Not really. From top of my head I could easily gather > 30 things at my house with the plain old USB A connector (several flash drives, keyboards, mouses, Bluetooth and WiFi adapters, smart card reader, external hdd enclosures, a stack of old laptops, r-pi, headphones, routers, playstation, tv, car diagnostics cables and probably several other things I can't remember). There are USB A connectors in all 3 cars in my family. And probably a dozen more devices with mini/micro USB - dslr camera, couple of tablets and older phones, dashcams, thermal imaging camera, powerbank...
Meanwhile there are exactly 3 devices with usb-c ports - 2 phones and one of several laptops (which also has several usb a ports). The only regular use of USB C for me is charging my phone. Everything else is on USB A or micro USB.
You might have some old legacy devices but that's not what I meant.
This reminds me of the USB transition with the first iMac. There was some angst but it settled down.
But I think most household will be using USB-A, USB-C, HDMI, and possibly lightning for years and years. My sister bought noise-cancelling Bose headphones last year and they still had micro-USB.
It hit me -- hey, solve this latency issue by using wired ethernet. Then I remembered, HEY, I already HAVE an adapter. Chained my apple-multi-port-adapter to my apple usb-to-ethernet adapter. Wait, why are things worse than WiFi? Oh, right, USB type A, probably USB2.0 or whatever. Limited to 93Mbps.
Go to apple store online, order Thunderbolt to Ethernet adapter. I've made the mistake of buying a USB-C dock instead of a Thunderbolt dock, won't make that mistake again!
It arrives, it's Thunderbolt 2 so it can't plug into my machine.
Order another one, this time USB-C.