The nice thing about averages in a large sample size is that they tend to be, well, average. By that I mean that something like a free throw, where a player will have a large number in the course of a season, the average can be a useful number to use to gain a perspective on growth and change and so fourth. Luck does not affect free throws in the same way that it affects other aspects of basketball or other sports. For example, rebounding is influenced by luck. It is not entirely dependent upon luck (there are all kinds of factors that adjust rebounds), but luck is a very real part of it. Free throws meanwhile, and shooting in general, what you see is what you get.
A number of people on this blog have taken Rondo very harshly to task about his poor percentage shooting and his poor percentage shooting free throws. And here's the thing about a players career average free throw shooting percentage. Wherever it starts, generally it's only able to improve about 10 percentage points. Some guys are shooters, some guys aren't. Just like some people are flexible, and some people aren't. So through effort and practice we can expect to seen Rondo touch 75%, or within a few points of that. But he's never going to be an 80% free throw shooter, he's just not. And I'm okay with that. Compared to other guards he's a poor free throw shooter. But, also compared to other guards he's a better than average on ball defender. He's a better rebounder. He's also a better passer. The way the Celtics are constructed Rondo's strengths are all in the areas where the team needs them to be. And on the other end of that his weaknesses are all in the areas where the team can absorb the problem.
Rondo doesn't need to be the 1st, 2nd, or 3rd option on the offense. The team is better when he isn't. The losses to the Lakers are a great deal more complex than Rondo's poor free throw shooting. I think you could take the following list and make a stronger case that any of these were the greater problem, or the combination of them, particularly in game 7: lack of offensive diversity (Paul Pierce ISOs work better against Ariza than Artest), uneven officiating, and Pau Gasol being absurdly good. Rondo has the same offensive skill set at Tony Parker, except he's better at almost everything, and once upon a time Tony was included in the discussion of "Best Point Guard not named Steve Nash." Yes, okay Tony was/is a better free throw shooter, but I'd argue (and based on statistics I'd be right) that Rondo's defensive contributions affect final scores more than Tony's superior free throw shooting percentage would. If I could snap my fingers and turn Rondo into CP3 would I? Absolutely. But if Rondo comes into this year the exact same player he was last year, in my green tinted eyes, the Celtics are still the best team in the East. And if Rondo comes back, even 4% higher in true shooting percentage, then the Celtics are the best team in the league, regardless of which sunglasses I'm wearing.
I know there are going to be a lot of people that disagree with my assessment of Rondo. And that's fine. I'm ready to defend this position with numbers and logic if need be.