CBS has had modern-day Sherlock Holmes series in development at least as far back as 2001. (I have the pilot script for the 2001 version of "Elementary," which is set in Malibu Beach, of all places.) Sherlock and its success showed them that the concept worked, and they pulled the trigger on something they had been wanting to do for some time.
That's very interesting -- I didn't know that. When you say the 2001 version, do you mean Robert Doherty was pitching the series that far back, or do you mean it was a distinct modernized-Holmes premise from a different creator?
Sorry, I should have been more clear. This is what I get for typing quickly.

Short answer --
The 2001 "Elementary" wasn't by Rob Doherty. It was by Josh Friedman. CBS has been soliciting scripts and pitches for a present-day Holmes from producers going back to 2000, only they kept passing on the scripts until Sherlock showed that the format worked and they bought Doherty's pitch.