A nation of electricians and HVAC technicians is not likely to be a world-class military, economic, or technological power. Sure, they're all good and fine trades, but a broad-based economy is best for fostering the kind of environment that innovates, builds, and grows.
If these kids are bright and good students, try medicine, including nurse practitioner, physician assistant, physical therapist.
Again, all honorable service professions. A little weak on the R&D side, however. There are a few MD types doing research, but not many. I was part of a research group looking into treatment modalities for glioblastoma multiforme, a particularly refractory form of brain tumor. We had some neurosurgeons on the team but the only one who was any kind of scientist was from Japan. The US neurosurgeons were more like neurocarpenters, more interested in mechanical techniques for obliterating a tissue mass than solving the problem from a systemic approach, which, given the broad-based nature of the malady, was what was required.
The point is, a purely service-based economy is not one likely to be vigorous in producing new and better industries. Remember, none of us would be here doing what we're doing now (using a computer on-line) if a team of scientists working at a US research laboratory had not developed the semiconductor electronic device that replaced the vacuum tube. The transistor was invented by a team of physicists, not cosmetologists. Similarly, the superheterodyne circuit, the developmental basis for all modern wireless communications devices, was invented by a EE, not a hairdresser.
I wonder what inventions will be made in China and India when those countries become the world center of technology. Possibly they can surprise us, after all they were leaders in the past.