In my humble opinion...
I'd rather read a terrible romance novel than a terrible sci-fi or fantasy novel. Because the worst romance novel I have every read (and trust me, there is no lack of contenders for that title) is still more put together and believable than the worst sci-fi/fantasy I've read.
I think the reason is most of the romances are set in the real world or in a historical context, which makes them more likely to be internally consistent in certain aspects. Physics will work like physics is supposed to. The sun will rise and set correctly. Rain will fall down, streams will run towards the sea, and in general the setting of the story will behave like the real world that people are use too. This is not always the case when you have strange science, other worlds, or magic in your story. So there's more chance for an author to screw something up in such a way that the readers are going to notice.
Then again, when the worse fantasy novel you've ever "read" is Heroes of Destiny (and by read, I mean looked at 3 pages and ran away laughing hysterically), a romance novel has got to be pretty damn shitty to even come close.
I think the reason is most of the romances are set in the real world or in a historical context, which makes them more likely to be internally consistent in certain aspects. Physics will work like physics is supposed to. The sun will rise and set correctly. Rain will fall down, streams will run towards the sea, and in general the setting of the story will behave like the real world that people are use too. This is not always the case when you have strange science, other worlds, or magic in your story. So there's more chance for an author to screw something up in such a way that the readers are going to notice.
Then again, when the worse fantasy novel you've ever "read" is Heroes of Destiny (and by read, I mean looked at 3 pages and ran away laughing hysterically), a romance novel has got to be pretty damn shitty to even come close.