Baint and switch is an aaaage old tactic, and why on earth wouldn't you use such a tactic?
This isn't bait-and-switch. As the link that mouser provided defined,
a bait and switch is a form of fraud in which the party putting forth the fraud lures in customers by advertising a product or service at an unprofitably low price, then reveals to potential customers that the advertised good is not available but that a substitute is.
Google isn't promising that you can have ad-free services but not delivering on the promise. All they're doing is introducing services at a low (or free) price so that people get used to them, and then increasing the price (in the form of advertising). How many times have you seen a "special introductory offer"? I bet you've even used them a few times. That's all that you can accuse Google of.
But really, what can you possibly expect? How in the world can anyone give you services without paying for it some way? Someone has to do the programming, the servers, hard drives, bandwidth, power all have to be paid for somehow. Surely you didn't believe that there are people financing this who are just looking for a way to pump their money into providing free services for you.