zeal for the job is almost irrlevant.
When I joined nats in 02 i thought that all big planes were boeings, and all little ones were cessnas. didnt really have an appreciation of what atc was. Saw it was big money, thought it sounded alright, good working hours etc. good leave allowance.
now I have been valid for a couple of years and do two sectors my knowledge has obviously increased as you cant avoid it when you are surrounded by aviation all day.
But, I don't think I would have had an easier time validating if i had spent my formative years at the side of a runway with a telephoto lens or played atc sims on my pc.
It is an aptitude for the job that should be looked for in recruitment, not how much they want to do it.
I really wanted to be something exciting like an astronaut or a footballer when i was ten. You don't always get what you want.
With the appaling wage we now offer our trainees, we are cutting out a massive pot of potential recruits. The likes of which have families/other commitments that mean they cant take the wage drop even if it would only be for a couple of years (as long as they dont get chopped at any 3 month interval).
I have heard people say that "at least they get a wage, trainee pilots don't."
Well Trainee atcos dont get to fly planes, they get to sit in a boscombe b&b reading the most boring manuals in the world in the hope that one day they can sit in a dingy room at 3 o'clock in the morning talking sh1t and eating crisps.
Why you want to apply shouldn't matter.