Why isn't Apple Pay taking off?

Google, Apple, Facebook (GAF)* are all trying to crack mobile selling.
Yet none of them have. And the signs are that they won’t crack it in Britain soon.
Why is this?
Well it’s not an impossible nut to crack.
China has done it. Recently there have been reports of cash disappearing in Chinese cities as people use their phones to pay for everything. Restaurants, taxis, coffee shops and even buskers take mobile money.
And Kenya’s been developing mobile money for years, well ahead