Each have their own definitions and ethic (or maybe aesthetic is a better description). Google have a strong advantage in discovery. They have more influence on "discovery" of everything from podcasts, books, applications, journalists, and everything else than any other company. They certainly use that weight. They can get users to any of their products. But, it is true that these products are not usually very lock-in. Search is very easy to switch from. Gmail is pretty easy. Network effect products like Wave, talk, circles, hangouts are actually the products Google has had trouble getting traction with. They got users, but not the lead in their markets.
MS have "weight" with OEMs and decision makers at companies from one man shows to fortune 500. They use that, which creates a nasty distance between liking the software you personally use and the decision to keep using it. Even Berkshire Hathaway's website is made with frontpage.
Apple have an interesting version of this. It may be their achilles heel, but it's also made them bold and creative. Apple products sell to the public, not to businesses and not through businesses. They don't rely on deals with OEMs, retailers, distributors, corporate buyers or telcoms to make sales. They don't even rely on discounts and competitive pricing. They definitely don't chase price/feature niches. More than any other company they rely on sheer consumer demand for their products. That means they would find it very hard to survive a "Windows Vista" period of ambivalence about their products. The trait is probably a long term liability. But, it is a version of level paying field, win by winning approach that produces bold product decisions.
All three are "cheats" by some standards, including (probably) the standards of the other two.