Regular USB had all the same problems. I can't charge my JBL speaker with my iPad charger. And I can't charge much of anything with my older Toshiba laptop USB ports.
Why anyone thought it would be different this time around, I don't know.
Different classes of failure though. Older USB ports would just fail to work (in the majority of cases), whereas with USB-C there is the risk of damaging the device.
First of all, Apple came up with a slightly different set of resistors on the data pins (leaning that the data in and data out will read slightly different V) to signal to their devices that they could go above 1A draw while charging.
The official charging spec says to put a resistor between the data pins (inside the charger to support detachable USB cables), or simply to short them with a blob of solder.
Your JBL speakers are likely reacting as if it was plugged into a normal USB port.
also keep in mind that the charging spec came about as China and EU wanted to deal with the piles of incompatible chargers that was going into landfills.
Thus older USB ports max out at 5V 0.5A, as that was the spec back when USB 1.0 was launched. Also why some external HDDs come with a Y cable that draws power from two USB ports to get the motor spinning.
what you're describing is simply that those ports were not designed to deliver a lot of amps because usb devices at that time did not need it. i dont think it's the same as not being fully spec compliant at the protocol level. i've never had 2 usb 2.0 devices refuse to work together.
Why anyone thought it would be different this time around, I don't know.