Technically not a monopoly but colloquially I disagree.

They account for 30% of the global market. They own key brands, license key premium names, and control key distributors like sunglass hut and LensCrafters.

Their cost to manufacture vs sale price shows a clear ability to price like a monopoly. As does their ability to box out competitors.

The $10 look alikes are not identical. They generally are cheaper materials, not polarized or coated, etc.

True for the $10 ones. But you can get very nice sunglasses with coating and polarizing lenses for way less than RayBan. RayBans are nice glasses too but you are mostly paying for the name.

>Their cost to manufacture vs sale price shows a clear ability to price like a monopoly.

No, it doesn't. It shows there exists demand for their products at that price point.

>As does their ability to box out competitors.

They have none. Anyone can go to various websites and order cheaper sunglasses that work just as well, or go to Costco and buy them for $25.

> Their cost to manufacture vs sale price shows a clear ability to price like a monopoly

Again, you are getting confused by branding vs monopoly. They sell luxury goods and can mark them at wild premiums, same as Hermès and Ferrari. None of them are monopolies. Very far from it.