Top 10 picks are not necessarily a guaranteed success, but the odds of getting a Pro Bowler are 1 in 3 for the Top 12 picks. That is pretty decent odds.
Since 2002's draft, 24 draft picks in the top 12 spots have made the Pro Bowl. That is 24 out of 72 picks or exactly 33%.
For picks 13-32, that goes down to 17 out of 120 picks (14.1%).
For the 2nd round, only 14 made it out of 192 picks (7.3%).
For the 3rd round, only 7 made it out of 192 picks (3.6%)*.
For the 4th round, only 6 made it out of 192 picks (3.1%)*.
* The 3rd and 4th rounds actually have a ton of compensatory selections, so the percentages are actually much lower.
So based on the numbers, the higher you draft, the better chance you have for an impact player.