I'm convinced that's the reason, the only place I've seen actively promoting that they take contactless payments is the local McDonalds Drive-in, and that's a sign tacked on to the menu/price list board, literally at the bottom, 3 or 4 inches off the ground.
Since the launch of Apple Pay, I've been looking at the scanners at the tills, and most of them seem to have the contactless symbol, but you'd never know you can use it, there's no promotional stuff for it.
MY local Tesco issue contactless cards via their own brand bank, but don't accept them at the tills. I suppose that is more to do with the limit of £20, as virtually everyone spends more that £20, making the installation pointless. If fingerprint verification removes the limit, combined with a decent promotional push, it could take off in a big way here.
Most people are already set up with contactless, they just don't know how to use it.