“Take the lead” is certainly an expression used in the UK to denote guiding people, as in “I’ll take the lead”. I assume both come from ballroom dancing.

I’m sure it’s used elsewhere but it may also simply be a conflation of the two.

I think you’re underestimating the intelligence of average people. There’s definitely a lack of knowledge, but average people are plenty smart to invent everything you’ve listed. It just takes time and is an iterative process.

Whoa whoa whoa, I’m not THAT depraved!

Double-spacing was taught into me when I was taught typing and I’m never stopping!