It's unreasonable to expect one cable type, because the additional costs for cables that support very high data rates or very high power delivery are prohibitiv

It's unreasonable to expect one cable type, because the additional costs for cables that support very high data rates or very high power delivery are prohibitive for cheap devices that don't need those. What they do need to do, though, is minimise the different cable options and make them easy to distinguish. My suggestion would have been to have a basic USB-C cable with exactly two optional designations: +FAST and +POWER. It's then easy enough for a device to say "this requires a USB-C+FAST cable" and consumers to then look for the same.