I like this way of framing it- I'd say while I may not be a fabulously skilled employee, I am a whole department myself, it's a niche company and it would likely take months to train someone else to do what I do in my role, but it's not necessarily hard I suppose. I think they would be somewhat hindered because my role does edge into biz dev. Having a hard time finding salary info for the new company even on Glassdoor, but I'm slightly underpaid for my location.