I'd argue that ordinary programmers can perform the same *type* of exercises if they:

- Put away a few weeks and go into Hermit mode;

- Plan ahead what projects they have in mind, which books/documents to bring with them. Do enough research and a bit of experimental coding beforehand;

- Reduce distraction to minimum. No Internet. Dumb phone only. Bring a Garmin GPS if needed. No calls from family members;

I wouldn't be surprised if they could up-level skills and complete a tough project in three weeks. Surely they won't write a UNIX or Git, but a demanding project is feasible with researches allocated before they went into Hermit mode.