Eh, nobody wants a chunky cable and connector to handle 240W (maximum USB C can supply), and these days it is certainly not cheaper that a buck regulator.
Copper isn't cheap and the conversion losses are going to be less than the losses to heat from lower voltages. The industry has responded with very high efficiency 50V capable converters.
Another advantage of USB PD is that with the PPS mode the device can be even smaller, featuring a lower power charger for non-PPS supplies, and using the PPS mode when available for higher power charging. None of these phones that charge at 50W+ have a 50W variable mode buck regulator in them.
The cabling situation isn't ideal. Hopefully it will improve. At least you can be fairly sure that most things will charge with any random cable though, just maybe not as fast as you would like. I use it to reduce the number of chargers I need to take with me on tips. I just bring one for the laptop, and plug everything else into its USB ports. If I need a quick charge I can plug that one charger directly into a device, but I mostly just do everything overnight.