Write your own OS? How about writing software at all? The future will be a world where "consumer" computers will not be allowed to run software that was not approved by some corporation, and where programmers will have to pay an annual fee just to have the ability to program (which could be lost without notice and without any refund).
"Back in my day, we learned to program by just programming! I used to practice my programming skills on whatever computer I could get my hands on when I was your age...you kids will never understand how much the world has changed..."
