I and many people I know ride a couple hundred miles a week on public roads for years and years, and surprise, we're still alive, have all our original body parts, and aren't scared little rabbits while we're doing it.
You haven't met your "driver looking at their cell phone at facebook of fate" coming directly behind you yet. Like you, I have been riding along with traffic for 40 years. I've done it in bicycle hostile territory such as western Pennsylvania. 6 months ago I very narrowly missed getting rear ended by some ahole in a BMW and wound up with a broken rib / punctured lung. Don't ride during the work week anymore, just the weekend and in low traffic density areas.
I've talked to a person who trained for RAAM and he's not riding as much on the street anymore either. Mostly mountain biking now.
Have you paid attention to the number of people talking on their cell phones while driving lately? TONS of them in Southern California. This should scare the shit out of any sane cyclist. Just today I had to slam on my brakes when some cell phone ahole almost ran into me as he erratically cut in front of and into me to turn off a freeway. Just because you have not encountered one of these people yet, does not mean the problem does not exist.
When you put an electric motor on a two wheeled vehicle and start inserting yourself into this stream of traffic, things get worse, a LOT worse. I also ride a motorcycle and have seen what can happen already.