Nightguards, a dental conspiracy?

Keep discovering more people I know who wear these nightguards in their mouths to fend off nocturnal teeth grinding (allegedly). They cost about $800-900 and aren't covered by insurance. Hmm...

Three close friends have them, as revealed the only three times the conversation has come up (100% hit rate!). A colleague who works in the office next to mine ALSO has one. Her dentist told her: "I'd be concerned about your teeth if you were 60 years old, even 70." Which is the same line MY dentist (different from hers) used to scare me into getting one (attained June 2010).

The dentist couldn't tell if the wear & tear happened years ago OR UP TO AND INCLUDING LAST NIGHT! Another dentist in the 90s suggested I get one, so I relented this decade.

Are we really that stressed out? Are we playing into a dental windfall, our mouths a glittering cavern of glistening coins to be mined by the DDS?

Am also left to wonder at the common element: me. Is there something I'm doing that's causing us to collectively clatter and clack into the night with these damnèd things? If so, sorry.

I never had dental-related anxiety dreams before, now every few months I dream of mortifyingly pulling out a ever-replenishing supply of top-row teeth, the row my nightguard is fitted for. Is the subconscious message: "Hey, you're too stressed, maaan." or is it "Get rid of your teeth, they're playing right into THEIR hands!"?

Questions, QUESTIONS! Conspiracies! It's enough to make a person REALLY stressed out!

[Jaw clenches, teeth grind so hard that fragments of enamel ignite into sparks, scalding inner cheeks]