So I assume that your third attempt based on "becoming their competitor or improving upon" strategy.
If so, how difficult was it (or how long did it take) to get organic traffic/customers through google, etc. Since I would think your competitors were more "established" in the pagerank, seo etc.
Basically, I'm just wondering how hard is it to get traction against entrenched players. Even if your product were superior, you still need to draw traffic to sell and prove it.
Don't give up. Make a free version that only generates 3-5 passwords. No one will buy just based on the screenshots... everyone wants to try something out first. That's what I did for my android app, and now I get a few sales a day.