Ryanair and Easyjet offering Luton to Copenhagen about 6 years ago for £10 one way, below the cost of APD, and maybe 4 flights per day each way was not a normal situation - it was just an old fashioned fare war of 2 large airlines competing for overall dominance to see who would generally back down first. Ryanair won the dominance war.
I don't believe what happened is a valid indicator of the Luton-Scandi market