20-Year Prospect
According to the Bureau of Labor statistics, the employment group "Aircraft and Avionics Equipment Mechanics and Technicians" will only grow by two percent in the next ten years (source). Not exactly smart phones and electric cars, now is it?
That being said, there are few people able to perform this sort of work, and as they retire, new slots will open up for the next generation of aspiring clipboard jockeys. And while we're not putting more planes in the sky anytime soon, we are entering an era of drones—all of which will become regulated in some capacity by the FAA.
The cool thing about this job is that the "waiting pool" to get in involves steady mechanical or flight work, with a paycheck that's not too far off from what you're hoping to make as an entry-level inspector. No matter how long it takes you to make the leap, the jobs will still be there, and there'll be no reason to lose it once you have it.