You make a good point. IMHO carrying a mini-Bic as primary, a second mini-Bic as backup, and a third mini-Bic wrapped in wax paper and sealed in foil tape as reserve is a viable plan. You might substitute lifeboat matches and/or a spark-rod for the second lighter. A 'boots and suspender' sort might carry all five. All the units are small and light enough to make carrying backups practical.

But the law of diminishing returns starts to cut in after three IMO. Maybe four if your going into the very deep woods.

Survival aficionados will have some experience with a fire bow, plow or cord, and how to use a lens to start a fire. Impressive, and handy in a pinch, but seldom needed.