Does YC ever consider ideas that aren't designed to be billion-dollar companies? For instance, if someone was working on a next-gen diagnostics tool for VoIP, they might realistically be able to get to $10-20M, maybe 10x if things go really well. But it's hard to see that becoming a billion+ company under any circumstances.
It's OK to be working on something that's hard to imagine how it would grow to be a really big thing, that's how most ideas start out. (Apple made hobbyist computers, Google was another search engine of 1000 -- how big of a deal could they have thought these would become?). It's important to be open-minded to the pathways of how your idea could become something big as it keeps growing though, and it's good to stop and think about those ideas every once in awhile.
One of the biggest things I've learned from being around YC community is that most successful ideas start out as small but end up being very large. I would encourage you to think bigger about the fundamental problems you're solving and then how you can turn solving the immediate problem into something really big down the line. Hope this helps!
What advice do you have for such ideas?