Interesting thread this and a lot of valid comments.
I think it shows what difficulties most trading factions have with member numbers.
A few suggestions in a earlier thread ( sorry, cant find it ) might help with that ie, cargo multipliers for official factions ( i think x 0.5 was mentioned ) more in rp routes, more lenient admin rules ( relaxed rules on official faction flight times ) and so on. If i can find that thread ill post a link.
Convoy trading is more fun but getting peeps online at the same time, due to time zones, can be hard to do and again not everyone likes them either.
Anyhoo....nice thread and ill keep an eye out for more suggestions.