There are more museums in the US than there are Starbucks and McDonalds – combined

I have no particular problem with the plural of “Starbucks” being “Starbucks,” as “Starbuckses” would sound a little too precious, but how does the Washington Post get from the singular “McDonald’s” to the plural “McDonalds”?

There are roughly 11,000 Starbucks locations in the United States, and about 14,000 McDonald’s restaurants. But combined, the two chains don’t come close to the number of museums in the U.S., which stands at a whopping 35,000. The Washington Post.