For me, it did so. My latest project took 6 months until my site went to the top10 for 2 most important phrases (semi-competitive phrases). However, my visitors see my site for other phrases as well

. And this is the best thing about quality SEO... If you do perfect work you will find yourself ranked for more than primary phrases.
Low-competitve phrases can be taken over in 6-30 days. That's why I am focusing on very specific phrases as well

. They usually don't attract thousands of visitors but are very good source of profit.
And 1 site which I am working for got good rankings for very competitive phrase (235 000 000 competitors, it is high-competitive phrase) after 4 month. But it is an old site, which is very important in Google.