A key aspect of the Carmack approach (or similar 'smart hacker' unconventional career approach) is avoiding that situation in the first place. However, this also carries substantial career, financial and lifestyle risks & trade-offs - especially if you're not both talented enough and lucky enough to hit a sufficiently fertile oppty in the right time window on the first few tries.

Assuming one is willing to accept the risks and has the requisite high-talent plus strong work drive, the Carmack-like career pattern is to devote great care to evaluating and selecting opptys near the edges of newly emerging 'interesting things' which also: coincide with your interests/talents, are still at a point where a small team can plausibly generate meaningful traction, and have plausible potential to grow quickly and get big.

Carmack was fortunate that his strong interest in graphics and games overlapped a time period when Moore's Law was enabling quite capable CPU, RAM and GFX hardware to hit consumer prices. But we shouldn't dismiss Carmack's success as "luck". That kind of luck is an ever-present uncontrolled variable which must be factored into your approach - not ignored. Since Carmack has since shown he can get very interested in a variety of things, I assume he filtered his strong interests to pick the one with the most near-term growth potential which also matched his skills. I suspect the most fortunate "luck" Carmack had wasn't picking game graphics in the early 90s, it was that (for whatever reasons) he wasn't already employed in a more typical "well-paying job with a big, stable company, great benefits and career growth potential" so he was free to find the oppty in the first place.

I had a similarly unconventional career path which, fortunately, turned out very well for me (although not quite at Carmack's scale :-)). The best luck I had actually looked like 'bad luck' to me and everyone else. Due to my inability to succeed in a traditional educational context (and other personal shortcomings), I didn't have a college degree or resume sufficient to get a "good job", so I had little choice but to take the high-risk road and figure out the unconventional approach as best I could - which involved teaching myself, then hiring myself (because no one else would) and then repeatedly failing my way through learning startup entrepreneurship until I got good at it. I think the reality is that few who succeed on the 'unconventional approach' consciously chose that path at the beginning over lower risk, more comfortable alternatives - we simply never had those alternatives to 'bravely' reject in pursuit of our dreams :-).