No, use an adapter. Or dont use an adapter, if your computer still has the legacy ports. However, when you need to replace your keyboard maybe a couple years later, you should look for a USB-C ones.
I think this is a bit unfair, when you compare a well matured standard vs a new one. Early USB keyboards were quite a lot more expensive than PS/2 keyboards, but it went down in price few years later.
Well, the fact that you can use the same port for USB, upto 100W charging, display output, analog audio, and even external GPU, I think its pretty similar to the PS/2 case, except on a larger scale.
Same with USB-A HDD and USB-A thumb drive. This is not anything new. Common sense is always required when operating computers, or anything actually.
It is entirely possible. The GPU can act as a USB hub. Almost every USB-C monitors now have USB plugs, so I think it makes perfect sense to include that. All you need is a USB controller, the same way happened when HDMI and DP were coming into video cards and they started adding audio codecs.
DP was never meant to be a replacement for HDMI. It was meant to replace DVI, while HDMI was replacing RCA and SCART.
This actually raised an important point. In the launch event of the SP4, Panos mentioned that he couldn't bring the thickness of the SP4 below 8.4mm because of the USB-A port. So it is evident that USB-A is holding the industry back the same way RJ45 did.
You could argue that you don't need a tablet thinner than 8.4mm, and I agree, but it doesn't change the fact that it limits designer's freedom for future devices and form factors.
Now imagine that exact same case, except you don't need the adapter for that. The adapters exist because we are in the transitional period. Few years down the line, you wont need it anymore as all devices and peripherals (hopefully) will have USB-C
Barrel charging port cannot act as anything more than charging, so I would say it has to go away asap. Not to mention the industry never agreed to one standard on this one, the situation isn't any better than it was with cellphones before they agreed upon to use mini or microUSB.
There is no such thing as non-USB Type-C port.
That's why the V still has legacy ports for transition, the same way old laptops still have PS/2. Only Apple would have the infinite wisdom to replace every single port with USB-C.
However, little by little, you will replace those 20 devices one by one, and (ideally) you would replace it with a USB-C ones. In a couple of years, its probably going to be 10 USB-A, and 10 USB-C. Few years after that, no devices will have USB-A ports anymore, but you would have 18 USB-C and 2 USB-A. In that case it makes sense to buy 2 adapters for those two legacy devices.