@Sam Hah nah - do not google "MAMIL"

Just wear a scandalous outfit in a city center once and you'll learn that the sky won't fall on your head. You might even find it exhilarating, freeing. Wearing a boring common MTB or roadie outfit won't bother you at all anymore.

People at work think I'm weird for riding in bib shorts with trousers over top.

But bib shorts are like women's clothes - no pockets !

@Sam Have tried to search for gravel clothing? From what I've seen here, they seem to be more "civilized" than pure MTB clothing.

wait - we need special clothes for riding on gravel now ?

Well, it's not "we need", it's more like "marketers saw a new market segment to jump into, and given gravel sells well, let's call it gravel". From what I've seen, it goes to "rugged road" to "more casual MTB".

(without the gravel name, the "rugged road" would have probably sold as XC before, and the "casual ones" as "commuter")

hehehe imagine having to chnge clothes partway through a ride because you went from gravel to dirt.

The versatility of gravel is also seen in clothing :p

Gravel does seem like a reasonable substitute.

@Sam on your question about lamps that just resurfaced. Didn't have the time to read everything, there were powerful lamps powered by AA batteries in the past, but they became a rarety. I have for example a caving headlamp that is powered by AA batteries that can deliver about 800 lumens for 2-3 hours (I've seen that Petzl upgraded the Duo and delivers 400 lumens with AA batteries). But as said in the answers, power density is at disadvantage here.