I sincerely appreciate all of the comments. You've provided thoughtful points without labeling me as a 'chicken' or something worse. Again, my OP was a bit strong on the 'fear' and 'constant danger' theme. I do feel riding in traffic can be hazardous to our health, and my spine condition has elevated my consciousness of the risks.
I've been cycling for a very long time...solo rides, group outings, scenic tours, Katy Trail adventure, charity rides, etc.. Age 74 is coming up this summer, and I'm not willing to quit as long as I can still do 30, 40, 50 miles a day without needing a visit by paramedics. I love the sport. It's an important part of my identity.
I'm thinking about the various points of view expresses so far. In the meantime, today I installed a NightRider Lumina (700 lumens) light on the rear rack of one bike. I will be more visible than ever from a considerable distance in daylight, which provides some comfort.
Thanks for chiming in.