I'm confused by your numbers.
As far as your first paragraph, a good return is 8-9 percent of your investment--so if you invest 10K in purchasing a building, you'd want to make $800-900 profit that year, after all your expenses. Also, 2 percent of $300K is $6000, not $2000. I think the rule of thumb you mean is that monthly rents are supposed to be 2 percent of the purchase price on a rental property (not 8 to 9 percent, which is what you say), so a $100K investment rental would rent for $2000/month. The 2 percent rule is more ironclad for multi-family, not single family, where folks will go down to 1.5 percent, or whatever.
I'm guessing know this, but your post seemed confusing. I would look at all of Arebelspy's comments in the landlording section, plus the bigger pockets website.
On this forum, my sense is that people are extremely skeptical of buying rental property in big coastal cities like SF, Seattle and Boston, where the real estate market is generally overpriced relative to rents. The nytimes calculator is great.