For one, the sentence "Getting rid of QAM isn't a bad idea in the long run" is crazy. QAM is a general-purpose modulation technique used in numerous technologies. It has nothing to do with the evil cablecos trying to lock down their signal, or something.
Next, the sentence "the cable industry is currently lobbying the FCC for a rulemaking that would allow them to encrypt QAM" is hopelessly misinformed.
If you plug a QAM tuner into a cable subscriber's coaxial outlet, you'll be receiving data for a few hundred cable channels, but all but a dozen or two are _already encrypted_. The ones that aren't encrypted are you local ABC, NBC, CBS, Fox, PBS, etc. The ones that are encrypted are "expanded basic" services.
Why are these encrypted? In part to prevent signal piracy to protect revenues, but also in part because the content providers require it. If you're a cableco, you can't offer ESPN or HBO without encrypting the signal - ESPN and HBO won't let you.
I can't speak for my cableco employer, but I have never had a conversation in which someone said "I wish we could encrypt our clear QAM channels" - it's always been the opposite. It's much easier to offer service if you can get the signal to a customer without having to buy some crappy converter box or spend a lot of money on a high end settop.