All of that is nonsense. Just build it and launch it. Then the market will tell you what it thinks.
there are more cost effective ways of seeing what the market thinks besides disappearing into a hole and coding.
good hackers get leverage and sustainable competitive advantage by solving hard problems, or at least creating software that is difficult to write. saying it's not worth building anything that takes time doesn't make any sense.
And secondly, good hackers can be hired too; it is possible to replicate most things.
I think that valuable web entrepreneurs are, in general, good hackers and good businessmen. A lot of hackers think the business end isn't important and a lot of businessmen think the technology isn't important. They are wrong. You will probably have serious competition and you need to be prepared to compete.
This isn't a kind industry. A lot of teams get crushed. Your team ought to be able to compete on both the business and technical fronts.
edit: I noticed you are one of the founders of DropBox. I don't know a great deal about your product. But, as far as I can tell we agree. DropBox seems like a straightforward, simple, focused application.