Fire starting, or fire keeping?
You mention how much time it takes for some of them to get ready to start a fire. If they are doing the correct things, gathering the correct combustables, that may not be so bad.
I have seen plenty of scouts "start fires" only to yell to one of their partners, "Quick, go get some wood!" The idea being that starting a fire is one thing, but keeping it burning is another. Being prepared upfront to do both is what is important.

You do have a dilemma, it seemd to come naturally to me when I was a scout, but I can also understand how young people now adays have no natural need to start fires. Arsonists aside.
I guess if I were to teach a course in fire building now, the bulk of the time would be spent on teaching preparation; location, clearing the area, wind, fire circle or pit, gathering the proper combustables, proper assembly of the combustables, etc.
The least amount of time might be spent on striking the match.
I think fire building/maintenance is 95% preparation, 5% ignition.

I commend you for being involved as a teacher of young people.