Depends entirely on so many factors...do you want to specialize in environment concept work and matte painting? Or vehicles, mechs, weapons, hardware? Characters and costuming? Creatures? Or be a generalist? At the higher levels people tend to be specialists...though some folks can handle a pretty good range. People also tend to specialize in genres to some extent...Syd Mead or Doug Chiang for example would not be likely choices for medieval or high fantasy settings...just as Alan Lee and Brian Froud would not be the first choice for a futuristic orbital space colony.
Environment concepting seems to be gaining in popularity...it was always the ugly step-child for many years. I think people still tend to be more interested in character, creature and vehicle design which means a bit less competition and pressure in environments.
So IDK what advice to give really, if you like environment design then go for it. Backgrounds, environments and worldbuilding has been the bulk of my career but I've done a lot of vehicles and characters as well. I like all of it so I work hard to be able to handle whatever comes along.
PS: Might want to move this thread to Art Discussion or Lounge...just more of a broad topic.
What would Caravaggio do?