Printers always had proprietary software. Not only that, but the reason why the Free Software movement was started was caused by a printer that Richard Stallman had in its MIT office and that the manufacturer refused to release the source code for its software!
> standard protocols
You still find printers that support standard protocols, such as IPP (internet printing protocol), that work fine without proprietary drivers with CUPS on Linux. You just have to spend a little more money and avoid consumer stuff, that is Inkjet printers, and go for network laser printers meant to be used in small offices. B/W ones aren't too much expensive, and you can find ones used for not a lot of money, or even free, since companies throw them out, that still work.
One oddity is that, through Linux basically piggybacking on the support printer manufacturers built in to get out-of-the-box printing on Macs and iDevices, the world of Linux printing support is actually really good for newish printers without needing drivers. There are a lot of AirPrint and IPP Everywhere printers out there.
I've had good luck in the past, as many have, with Brother's simple laser printers, but was very surprised at the ease of setup on Linux of a new Brother multi-function all-in-one inkjet printer/scanner combo thing: even the scanner worked over the network without a fuss. Night and day compared to my recollections of working with hpijs, hplip, foomatic, even poking around for Brother laser drivers sometimes for ones that didn't talk PCL.
But then you have things like this where there's a pointless app forced into the mix to add more friction to that improved story... just because.
> standard protocols
You still find printers that support standard protocols, such as IPP (internet printing protocol), that work fine without proprietary drivers with CUPS on Linux. You just have to spend a little more money and avoid consumer stuff, that is Inkjet printers, and go for network laser printers meant to be used in small offices. B/W ones aren't too much expensive, and you can find ones used for not a lot of money, or even free, since companies throw them out, that still work.