Actually Romance is probably a stronger novel genre than say Science Fantasy. The bulk publishers run several lines of novel length stories you can pay for, you can pick how "spicy" is OK for you (some cultures are like "OK, yes I like a plot but there is fucking in this story right? Do NOT cut away from the action"; Other readers will be angry if there's so much as a French kiss between our happily-ever-after couple, even if it's only alluded to and not actually described) as well as themes (Doctors? Werewolves? 18th century Dukes? Billionaires?). If you want pulp science fantasy there aren't a lot of options AFAIK.

On the other hand for shorts science fantasy is much better off. Apparently anybody who can knock out six pages of romance tends to use somebody else's character development as shorthand and so can only publish to AO3 but if you can knock together a decent SF story in six pages that's worth some cash from a pro or semi-pro magazine. Even pretty hard† SF, which is not a common taste, can shift enough copies of a bunch of shorts to make economic sense.

† Science Fiction is graded "harder" the more likely that if you ask "How does that work?" about something in the story the author gets as excited as Hank Green and starts explaining details that may or may not just be facts about our universe which they've incorporated into their story -- as opposed to "A wizard did it" or "That's not important". The diametric opposite of the MST3K mantra.