I've been in IT for 27 years, mostly as a field service engineer. I've stuck with it because I enjoy the freedom of being on the road, and interacting with customers, most of whom are pleased to see me, because they know that I can fix their PC/server/network/ATM/POS system/till, etc. I work on a huge range of different equipment, in places as varied as shops, banks, factories, MOT garages, and private houses.
I left school with A levels, as did 90% of the people that I've ever worked with. The other 10% have had college qualifications or degrees. The ones with certificates or diplomas made the grade, while those with degrees all jacked it in, because they couldn't handle the pressure. I've seen graduates come into the job, thinking that they know everything, and making fools of themselves in front of our customers. I'm not perfect, but I know who to ask when I get stuck, and I can keep the customer happy.
I was taught that years ago - fix the customer first, then try and fix the fault.
Being able to leave site with a happy customer, despite not having fixed the fault after 2 visits, is a skill you learn on the job, not in a classroom.
The money isn't great - $22K basic, +about £16K on call allowance and overtime, + lease car, healthcare, pension, etc - but it's enough for where I live (Cornwall).
The people who are getting into this line now tend to start as technical couriers, delivering and installing printers, screens, etc., and doing "quick fix" calls. The other route is as an installation engineer, fitting-out new shops, banks, etc. If they show an ability to think, they are given more responsibilty, and eventually get jobs as "proper" engineers.