20-Year Prospect
The future outlook for elevator installation and repair technicians is an uplifting one, to say the least, and particularly in crowded cities where building out is not possible.
This career has a projected twenty-five percent growth rate over the next ten years, chiefly because more and more people are moving to urban areas (source). Some cities are undergoing serious high-rise condo booms, which bodes well for the amount of work you'll be able to get.
Technology will continue to change, though, so make sure to stay current on your knowledge of the systems in use. All in all, the future looks bright. After all, there's nowhere to go but up.