Calpol and lemsip are not like for like. Those are products that include one or more drugs (lemsip is a cocktail), but the drug isn’t the entirety of what they are.

The yanks do it for everything. Like, in the example quoted, literally any antihistamine will do, but they rush straight to one specific brand of one specific antihistamine.

The only true counter example I’m aware of is salbutamol, which we almost exclusively refer to as “ventolin”, but they call “albuterol”