You realize a barrel jack is just some metal of a certain size right? Calling a barrel jack proprietary because dell added crazy things to their own power supplies is nonsense. Barrel jacks have been around and sold individually in bulk for half a century.
> You realize a barrel jack is just some metal of a certain size right?
The dimensions you use and the voltage you put across it and polarity you use all make the jacks incompatible. You have to use a Dell charger for a Dell laptop.
You could add those same DRMs to a USB-C connection and 'manufacturer required' power supply.
Barrel connectors are not proprietary just because someone implemented theirs in some specific way to harm consumers.
In fact USB-C connectors are more likely to implement a DRM, given that the connector comes 'batteries-included' with a data channel that won't need to be re-imagined.
Barrel jacks offer no such boot-straps to would-be DRMers. That isn't to say it's impossible (as HP/Dell/Fujitsu have proven), but a 2 prong barrel jack is going to require a bit more effort.
If you are using proprietary to mean 'consumer-hostile', use a better phrase. Proprietary has specific context to IP/copyright/design.
> If you are using proprietary to mean 'consumer-hostile', use a better phrase.
I'm not - I'm using it to mean non-standard and specific to an individual vendor. I can use my Apple USB-C charger to charge anything accepting USB-C, which is most things these days. I can't use my Dell laptop charger to charge anything except a Dell laptop. That's what I mean by proprietary.