I never got the spandex go-fast thing. 99.9% of riding is training, not competition. Football players run with parachutes to train. Bikers should wear bulky clothes, they wouldn’t have to ride as far and for as long, clearing the bike paths for others.
I ride a mountain bike on gravel, in jeans. On old logging roads with no traffic except the occasional, moose, elk, deer or bear.
He kept wanting all types of flashing lights/shoes and even helmets and continuing to ride on the roads often zero bike lanes.
Finally, his mother, an RN for all of her adult life told him he needed to do what you do and he does now.
So he stopped riding with his group and does your country thing after driving there and back in his OJ Simpson Bronco.
He does have watch out for deer, wild pig and the rare bear.
Spandex isn't about going fast per se (not aerodynamics-related), it's about preserving the skin on your bum when you're seated on a saddle that's tiny compared to what's on a kid's bicycle, your legs are pumping up and down 80 times per minute, and you're going to sustain that for a couple of hours.
Old cycling shorts were wool which, like spandex, is stretchy and will conform to your shape with minimum of excess. When the material gets wet (which it always will, because you're working hard and will sweat profusely), if it didn't fit snugly it would bunch up where you'd least want it ...right between your legs.
What a lot of people don't get is that to a 'serious' cyclist, riding is the same commitment as a part time job. 10-15 hours saddle time per week, which doesn't include time spent maintaining and repairing the bike and bike kit, and doing the laundry on cycling togs. When I was a younger man I routinely rode more than a thousand miles a month (except during winter). That's a lot of wear and tear on your back side.
Which is why all high-mileage cyclists are susceptible to saddle sores anyway but the traditional shape of cycling shorts isn't about the esthetics, it's about comfort and protection against saddle sores. There's also a wee bit of padding in the crotch area called a "chamois" (say: 'shammy'). A chamois is a European goat and back in the wool shorts days the chamois actually was made from the skin of these goats. But it was expensive and required the same care as other forms of leather, which is exactly what it was. Very supple leather. Chamois now are virtually all synthetic, but even modern shorts always have a chamois (even if it isn't made from goat any more) so you don't chafe from the friction of your legs going up and down in opposite directions 5000 times an hour.
Which is why cyclists do not wear undergarments under their shorts. That would only interfere with the function of the shorts and the chamois.
I learned all this the hard way. I thought all that flu-flu stuff was nonsense. Started riding in gym shorts, jock strap, T-shirt and Ray-Bans. But the gym shorts gave me saddle sores, the flapping of the (loose-fitting) T-shirts chaffed, and plain old Ray-Bans don't shield the eyes from 30-mph winds as well as streamlined sports glasses.
Now I wear all the traditional cycling garb (minus the team logos, where possible) because the cyclist's kit has been refined by more than a century of trial-and-error. And the design of every bit of it (except when helmets when through the "Alien" phase) is a matter of form following function, not the other way around.
For the better part, cyclists don't select their clothes to make a fashion statement, they're dressing to enable their body (particularly the perineum, AKA the "taint") to endure the stresses that cycling puts on it.