How do you have the cable correctly identify itself if you don’t put some smarts in it? Or are you saying we should only be able to buy expensive cables fully rated for 100W (or higher as the spec has been updated) — and how do you prevent an older cable rated for 100W from being abused in a newer 200W circuit?

Divider resistors are okay, but the IC is a better choice for future proofing and reliability.