Linux is free-as-in-speech software. That means I could clone it in a week and sell a competing product when, say Ubuntu, starts to implode. Free-as-in-beer software doesn't have that.

I think this is a false dichotomy, Linux is both free as in beer (unless you choose to pay for it) and free as in speech.

You're right it's not a dichotomy, but the property free-as-in-speech is the one that helps here, free-as-in-beer doesn't matter either way in this case (besides it's initial popularity).

There's a big difference between relying on a self-hosted product vs. a remote-hosted one. If your self-hosted software is suddenly no longer available, you have plenty of time to come up with a migration strategy, while you continue to use the obsolete product. If Yahoo Messenger went away, it would immediately disrupt business for all who rely on it.

Not to mention that any enterprise Linux user worth their salt has an expensive support contract with a major vendor (such as Red Hat). Either that, or they're confident that they have the in-house resources to support it. No enterprise user considers Linux to be "free as in beer", by any stretch of the imagination; rather, they're using it because it's the right tool for the job.