Voice Over is a huge industry with a bajillion different types of work. The common advice out there is to find your niche; the character type(s) that play to your strengths and the forms of work you naturally excel at. It helps you whittle down your demo into its strongest form and gives your marketing efforts direction, which is all well and good. However, seeking out and honing in on your niche - or what you think your niche should be - can be limiting, and prevent you from growing as an artist. I make a living as an actor not because I'm great at industrials or I excel at museum tours - I'd starve to death if I only did niche work. It's true that there's a billion jobs out there, but it's hard enough to do this for a living while also excluding huge amounts of work because it's not your focus. While it doesn't fit nicely on a business card, I work on explainer videos, corporate event openings, video games, cartoons, indie films, documentaries, movie trailers, commercials, podcasts, and on and on, playing stoic narrators, senior Star Fleet commanders, dragons, baby turtles, VOGs, straight men, comic relief, detectives, nerds, drunken demons, French Canadian Hockey players, and so on. I also do on-camera commercial work and print modeling, which I obviously wouldn't consider to be my VO niche at all, but it's paid work in the realm of acting. Am I equally great in all of these fields? Probably not, but hey, I don't have a shitty day job to make up for my lack of work while waiting around for the gigs best suited for me roll around. And, unless I'm mistaken, the world of casting directors aren't shunning me for occasionally turning in a bad audition. If you want to only do one type of voice work forever, have another career handy, because you'll never have enough work to make ends meet.
I guess it's the because anyone can buy a fifty dollar mic and open an account on Voices.com that makes people think they need to narrow down their options, but honestly, if you're not here to push yourself and find new things out about your voice and what it can do, then why choose acting as a career? If I only did e-learning modules or car commercials, this job would suck. Not because I don't like that kind of work, but because doing the same thing over and over again day in and day out - well hell, that's why I left the workforce in the first place. But look at it this way: you're an actor. Voiceover happens to be your specialty. I really don't find much value in limiting yourself much further than that.