Good questions. People wear lots of hats in startups, and cross-train to avoid bus factors. If someone has highly specialized skills, cannot pass on their skill

Good questions. People wear lots of hats in startups, and cross-train to avoid bus factors. If someone has highly specialized skills, cannot pass on their skills, and cannot be replaced, they are irreplaceable and the company needs to take other steps to resolve that for its own sake. Here's the question that answers all of your questions: What happens if that person quits? And the answer is, the company either adapts, folds, or had plans in place to handle it. Either they were essential and irreplaceable or they weren't.