That's why making regular updates helps promotion. If you take 1 year to make an update, you better have a good supporter base if you want to make good money. Or it's just a hobby and money helps mitigate cost of buying assets and hardware. But most hobbies cost money without making any
I would also prefer small but frequent updates. After all, a player can decide on their own whether to save the updates until there are enough content for a hour of continous play, or to swallow them in small portions as they are released.
I think developers don't like this approach because it requires much more careful planning of each small episode and a more complex story composition so that the small episode doesn't feel like a piece of story torn out of context with no beginning or end. Many fail at this, and these small updates are almost impossible to play on their own, as the flow and coherence of the story is lost.
Add to this a lot of complaints like "is that all?", "I wish they had developed it longer and released a proper update". In several games I've followed, when developers asked supporters which updates they liked better, they usually chose longer development times but larger content sizes.
