First, enterprise and industry are wholly dependent on Open Source. This kind of snuck up over time, and with big corporation supporting the Open Source software they need. So if all the programmers go because we can't teach elementary kids to "code" because they have no "real computer" to "code" on. First off, the desktop and laptop class computers *will* still be there. Second, the kids still won't learn programming in a classroom led by a teacher with no programming experience and who is regurgitating material from a book and doesn't have the foggiest notion of how to handle something that goes wrong.
Open Source is not taught, it is encountered and embraced. Open Source programming is community. Those people who have oh so specialized cognitive abilities will naturally gravitate into the Open Source world. Not everyone belongs there and the idea of introducing this into curriculum is a waste of time when they should be learning something else. Of the Open Source programmers I know and have otherwise met, not a single one of them were taught about it in school. However, many got started in programming at a pre-teen age.
You can cite figures of slumping PC sales for sure. But what about the balancing figure that shows people aren't buying new desktops because the one they bought five-years ago is still blazing fast. Right now I am writing this on a Windows 10 tablet. It's a great device but the quad-core Cherry Trail and four gigs of ram are nothing to write home about... oh, a Bluetooth keyboard and I can code away on this tablet. Next room over I have the desktop I built when I need serious horsepower for something or need my nerd fix. It is 6-core AMD machine with 16 gigs of ram, a 120 gigabyte SSD and, integrated video. That is straight of 2011 and I call that my fast machine.
I could get back into carrying on about Open Source, but this statement:
Fewer people have the opportunity to write code and share it.
Reveals the depth to which you have no clue whatsoever what you are talking about. There are plenty of people around here who might take the time to write a small book about it for you, but I am not one of them.