a) "denounced hero ball" pretty much means complaining when it happens, b) our pace was about 1 possession per game below the league average, I'll leave it to you to explain how 1 more possession for the team in a game would have a profound effect on those scoring averages and c) they were good, not great scorers.
Well yeah, I guess the fact that no-one took more than 15 shots per game is pure coincidence. Had nothing to do with team strategy. Heck, even taking 13 shots per game was unusual.
Yes, our strategy had to change because our leading scorers were worsening over time. In 2008 the bog three scored 57% of our points during the season. In 2010 that number was down to 49%. There's a reason for that. People like to think that PP and KG played like superstars through 2012 or 2013 and then suddenly fell off of a cliff. That's not the case. The dropoff in their play was pretty noticeable over time.
I can't replicate your numbers, so I've got no idea how you're calculating this. If you're using point totals, it probably reflects missed games. If you're using averages, it's not particularly indicative of anything, since you're not accounting for missed games in any way.
And if you can't see how taking 100 shots per game will likely result in higher individual scoring averages than taking 90 shots per game, I don't think I can explain it to you 
If you can't see that no team in the league takes 100 shots per game (only 1 team has even taken 90 a game since 2008) and the Celts weren't 10 shots a game below average in those years you can save that explanation. Also, you were talking pace, which is different than FGA.
Teams that play at a higher pace typically take more shots than teams that play at a slower pace. Do I really need to explain the concept of pace-adjusted vs. raw averages?! It applies for pretty much everything, including points and FGAs.
Rubio is a horrible shooter. And yet, he holds a career .330 on three pointers on a non-negligible sample of shots.
...which is still below average.
...but yet leaps and bounds above what Rondo was able to muster in his best season.
Rondo's best year was 31%, 33% isn't "leaps and bounds" better than that.
Well then, I apologize -- that year when Rondo shot 15 for 48 is only
marginally worse. Too bad that he's shot .240 or less in 5 of his other 7 seasons, though
