Barrel jacks were awesome, they could go in any orientation. The only downside was the many different forms of barrel jack and lack of a standard. My question is: why isn't there a cylindrical USB port? You would be able to rotate it any way you want within 360 degrees!
As a matter of fact, why isn't there a cylindrical power plug? You'd get the benefits of a recessed plug like Type-C (EU) and Type-F (Schuko), you'd get the benefits of reversible plugs like Type-A (North American) and more so as you get 360-degree rotation, and it would be MUCH harder to break/bend compared to two flimsy pins (the UK plug has three thicker pins, but a chunky cylinder would be much more difficult to bend than the pins)
If it was a hollow cylinder (a bit like a vacuum-insulated water bottle), you could feasibly fit some small electronics in it, so things like flush low-power USB chargers and smart home sensors could be made.
The contacts would likely need to be outside the cylinder, similar to the "neutral" pins on Schuko plugs. There would likely need to be some plastic tabs to keep the power bits from touching the non-power bits, and then the socket itself would be able to freely rotate.
Actually, why don't regular sockets freely rotate? Then it would solve all the issues of non-reversible plugs not able to go upside down and reversible plugs not able to go sideways.
Speaking of cylindrical objects, what happened to camcorders? They sound like the most comfortable and easiest way to record videos, with straps and everything. They were compact, portable, and wasn't heavy as all heck.
this is my rant about cylinders, thank you for your time.
Round connectors were absolutely used to transfer data, for example audio and video in the form of RCA plugs and many other examples back in the day. Another example is coax cable for TV signals (both analog and digital) and also LAN.
However the lack of distinct interface channels leads to a bottleneck in bandwidth. So as the need for bandwidth increased many of those were replaced with multi pin versions. This is much harder to do with round connectors and there isn't that much benefit, so they mostly got ditched.
However round connectors still have their place, for example tiny little coax connectors found in many devices to carry signals. Wifi antennas and such are connected this way.
Coax has only 2 conductors and it keeps impedance constant, unlike audio jack