There are probably quite a few non BC/BE people out there who have taken it upon themselves to learn it the right way. However, from experience and also from reading the literature, they are in the minority.
From personal experience, taking checkout at rural places from part and full timers (for years!) that aren't EM, you can distinctively notice a difference. Things that make me pucker, they don't seem to even notice. One guy checked out a WPW in a fib to me. As he was talking, he said "Yeah, I put them on a cardizem drip, just waiting on cardiology to call back for transfer." They weren't in RVR, just slightly tachy at 108 when he started it. I cut checkout short to go personally stop the drip. Unfortunately, we all have gaps in our knowledge, but at least the EM people had to learn the "real bad stuff" in the theoretical in residency. The PC people learn some, but it isn't the same. And since they didn't work in an ED for 24 months of their residency, they weren't exposed as much then. Just a fact of the numbers needed to learn.
Yes, and for basically the same reason. While you may not be the "best" by whatever metric, you're likely pretty adequate. However, not all are the same. I've seen FMs lose their scoping privileges after too many perfs.
For the vast majority of EM, you never need to do something "right now." You can always go look it up, and many people simply don't out of pride or not being aware that they don't know the best way. There's also the time issue. But those "right now" moments are what make the difference.