As long as the cable isn't completely broken and has wires that actually conduct the current, you're getting 60W over USB-C PD. It's 100% passive. Compliance means "it connects one end with another without causing fire", it only gets more complex at more than 60W.
If it doesn't have the wires inside, you've been scammed into buying a piece of junk that merely looks like a USB cable.
When using a USB-A charger, you're guaranteed* at least 2.5W, and the charging standard (BC 1.2) goes up to 7.5W (though usually you can go higher with proprietary protocols, such as QC, or even PD 1.0, although it's very rare for something to support PD 1.0 and pretty common to support QC or Apple signaling). Sure, you won't be able to charge a laptop from a USB-A port, but it's not a hard thing to grasp.
I don't think you know what you're talking about.
* You could probably find some chargers that do less than 500mA, but you'd have to search among 20 years old ones at this point and they wouldn't really work with anything modern anyway, PD or not. The hard requirement is that a port has to provide at least 100mA, but that's only relevant to data ports that can do USB enumeration - for charging-only ports, everything assumes at least 500mA, and it would be really hard to find something with less than 1A or even 1.5A (7.5W) these days. Of course, if you try hard you can find any kind of weird stuff out there - I've got a water fountain for cats with power adapter that has a USB-A port providing 9V, so connecting anything else to it may make it release its magic smoke - but that's hardly a problem with USB itself.