If your only professional experience is OCaml and you want to look elsewhere for work then your opportunities shrink noticeably. Especially if you're looking for a position that requires experience. It's much more digestible for a company to hire someone out of college and invest in training on tooling. But many companies won't get past the resume if a senior developer has to take more time to on-board.
This is likely true for many companies. However, it is also a metric for what type of working environment it will be. I value being able to learn quickly and creativity over pre-training.
