They have fixed this, the modern spec has speed and power rating logos that (good) manufacturers can put on the cables. Just assume anything without a logo on it is USB2/5v only and buy some new cables you know the specs of.
The fact that cables have varying speed and power seems like a failure at launch. Who benefits from this? Manufacturers trying to save money on cables? Fuck that. This just means we'll use the cables that actually work everywhere to death and throw the rest out. What a waste.
Well, there are always going to be varying speeds and power because needs change and tech improves, as the spec improves over time, the cables have to vary. Either you change the cables entirely (creating even more waste as now you have to change even if you don't need the higher spec), or you have varied ones. Also, right now they can do higher speeds at shorter lengths, but not longer ones, so if you had only one speed, you'd have to have a short maximum length, or pay for very expensive active cables for any long cable, even if you only need it for power.
Even if it were purely cost, even then I think we still benefit: the alternative is cheaper devices will use a different cheaper cable spec, and you end up with many different cable types where you can't use them at all. Sure, maybe I won't get max speed from one cable, but still being able to get half speed and or power is better than a cable I can't use at all.
Honestly, I just have never got this criticism, the alternative is just "have completely different cables" and that has literally all the same problems but worse, outside of "it can be hard to identify what this cable supports", which is solvable in much better ways than making them incompatible (as with the cable I'm looking at on my desk right now which explicitly says 40gbps/240w on it).
I grew up in the era of every mobile phone having a different charger, and it was always a nightmare when you were at a friend's house and they didn't have the one you need. I may not get max charging speed, but now everyone always has a charger I can use for any of my devices. Please, I don't want to go back.
Most people do not need 40gbps/240w USB cables, and will be fine with older spec ones for a long time. Yeah, power users might go out and replace all their cables, but most do not, and even most power users will still relegate older cables to lesser uses (e.g: charging lower-power devices).
