This happens to me most of the time on short haul flights in Europe. They basically sell higher priced tickets with two items of cabin luggage and the lower price tier effectively turns into zero items.
FTFA: “Passengers will now be entitled to both a free personal item measuring 40cm by 30cm by 15cm and a small wheeled item with a maximum total dimension of 100cm and a weight of up to 7kg.”
Sure. This legislation directly addresses that. It creates a right where there previously wasn't one. A right which solves OP's problem.
I read "entitled" as granting a right. I've tried searching for the draft legal language, but am having no luck.
Opt out versus opt in. If most people pay for it, it should be included in the marketed price. (The ones airlines compete most aggressively on.)