I'm sort of under the impression the spark lite isn't producing enough spark.
Not everyone realises that with Spark Lite it makes a difference which way you spin the wheel. There's an arrow printed on the orange stick to show the correct way. The wrong way doesn't produce many sparks.
Would the tinder quick have dried out if you stored it in a container like an Altoids can or something?
I don't think it has volatiles. It doesn't come in special packaging, and I have some that's been left out for years that still takes a spark. It should be very reliable.