Like Starbucks , it is a very big company/ industry and it accepting bitcoin
is a very good thing for bitcoin.
Even Steam has started accepting bitcoin .
All these things show that bitcoin has a bright future.
Slowly MCD , KFC and many more will start accepting Bitcoin.
With the current acceptance I do not think that the adoption is slow as the companies you have mentioned will convince much more companies to adopt bitcoin I am sure that till the coming 5 years bitcoin will be on more than half of the world.
Although we are doing it slowly this are really big steps into becoming one of the best online currencies. Well, we cant deny it, this world is getting better with technologies. Almost 90 percent of people do have a smartphone which could easily access the internet. KFC is a worldwide fastfood so it would really spread so fast with this adoption.