> Google Maps Is Not a Directory. It’s a Market Maker.

I understand the author's meaning, but this isn't what the term "market maker" means. To "make a market" is to stand ready to buy and sell, usually a security, in order to create liquidity in a market. Usually this resolves the issue of timing, because it is unlikely that someone wants to buy at the exact moment someone else wants to sell.

So to "make a market" in London restaurants, Google could buy food during the day and sell it at night when the shops are closed but people are hungry. (This would be silly.)

Perhaps a more precise term is "algorithmic gatekeeper."

However, market makers have some leverage on the market they operate in, that's what the author probably meant.