There are generally two factors that heavily favor simple questions:
- Human nature
- The formula for "hotness" for the Stack Exchange™ MultiCollider SuperDropdown™.
First is human psychology: When someone comes across a post, their attention span usually lasts less than 10 seconds before they will click away.
If the question cannot capture the reader's attention within those 10 critical seconds: No vote.
The same concept applies to the advertisement and marketing industry.
Simple posts are easy to understand. So they are most likely to be read and understood within that 10 second time-frame. That's why they have a tendency to get upvoted more.
However, longer and more thought-out posts usually fail this category:
- Reader comes by...
- Reader sees a wall of code. (or a wall of text)
- TLDR - Good bye...
All long posts are severely handicapped since they cannot be read in 10 seconds. So the only way they will get a lot of votes is if they capture the reader's extended attention within those first 10 seconds.
From my experience, here are some things that capture attention very quickly:
- Fancy formatting: Use those bold and italics wisely. (But don't overdo it!)
- Images: Everybody love images.
- Humor: It might get you downvotes, but it'll get you many more upvotes to offset them.
Second is the "Hotness" equation:
Simple and easy questions tend to bait a LOT of answers (as a result of FGITW).
Put that into Jeff Atwood's formula for hotness, and we see that these simple questions get extremely high on the Stack Exchange™ MultiCollider SuperDropdown™:

(Bad example here, since that question isn't exactly that simple. I'll replace it with a better one the next time it happens.)
When a question gets to the top of the hot-list like that, it invites lots of views from users all over the network. And when you get a lot of views, you get a lot of votes.
For hard questions with few answers, there isn't much you can do here.
I've seen far too many answers that never got the attention they deserved, because there were not enough answers to bump the question up on the hot-list.