I think we should teach our kids the whole process from ideation to product design to UX to coding to testing. Some will gravitate to the more artistic side of the world and others to the more engineering side. We are all wired differently and we should expose kids to the spectrum of possibilities and let them gravitate as they choose. I don't have an artistic bone in my body, but problem solving came pretty naturally. i had no interest in art or drama classes, but i enjoy art and admire artists. We don't teach kids history because we have high demand for historians. We don't teach kids music because there is high demand for musicians. we teach kids these subjects to expose them to the possibilities and to produce well-rounded adults with a broad range of experiences, often times to the detriment of preparing them for the realities of todays job market, but that's a debate for another time. With the limited educational $$ and resources we have i would prefer to see more STEM options.
Depending on what you are building the project can be built by 1 or hundreds. If you are building a chicken coop for the back yard - 1. If you are building an office towner - many. Designers design, architects architect, engineers engineer and builders build. Some specialize even further (foundations, framing, interiors, trim, etc.). Knowing at least something about all the 'trades' and how they interface makes one more efficient and valuable to the overall process. The best architects and engineers i know are those that have experience actually building stuff, but that doesn't mean they are an expert in all aspects of creating a building.
@ Douglas B, our current company is closely tied to students and schools. Helping to spark interest in kids for STEM is a personal passion. I'll ping you off line to discuss.