The "complications" are basically employer and manager propaganda because the information asymmetry suits them better than people realising they are undervalued and leaving
For the low-paid, it can make it even harder to get credit, or a place to rent, and it can be used for other kinds of discrimination. For the highly-paid, service providers and sales people can use the information to increase the prices you pay and make negotiation harder.
Parasitical private equity firms maximising their prices is a reasonable worry.
Obviously it's not perfect. But as you say, it's a difficult problem. And salary ranges are at least something