I agree that very bad luck with injuries has played a major part in us not winning more titles these lats five years, for sure.
However, I agree with the Op to an extent here as well because outside of the 2008 bench/team, every year we've put together a hodge podge bench - new players, new guys for our core to adjust to, etc.
I wrote a post after the 2009 bench was put together titled "If you're going to buy a Rolls Royce, don't put bicycle tires on it".
I was disappointed that we had put together a dream team trio with a short window and then had cut them short with the right bench to maximize their talents.
It's true that had KG been 100% healthy in 2009, I think that would have been enough to get us a title in 2009 and also had Perk not gone down in game 6 in 2010 we also would have one a title.
But something can be said for the fact that we've had to "reload" every off season with new players. Continuity is very important for championship teams - most of the teams that go on runs, do it with a roster that's been together for a number of years and that isn't changed up every off season.
I thought it was a mistake to let Posey go - he would have declined in skill but in our system and motivated by our vets I think he probably had another couple good years in him, year three you back him up more with a Marquis Daniels or Pietrus type, year four you can trade his expiring...
I also thought it was a mistake to let Tony Allen go - he provided major toughness and intimidation to this team. I would argue he may have been enough to get us by Miami last year - because Wade had an absolute layup line to the rim with Ray on him.
I also think an argument can be made that were he on this roster this year, we'd also be in the finals, for two reasons:
1. Wade would be in a bruising battle with Tony for 20-25 minutes a night.
2. When Lebron was going off in game 6 - Tony Allen would have been brought in and because he has an absolute pit bull mentality on D - he would have been way, way, way up into James. Would have completely changed that game and LeBron's momentum.
So, for me, the big mistake was not going all in and speniding even more money if you had to to get three long term bench additions for this team:
1. A quality 4/5 (someone like Jason Thompson, Kurt Thomas)
2. A quality SF for Pierce (Posey)
3. A quality Combo guard or back u[p off guard ( TA would do)
Then let that starting five and those three key guys, play together for 3 to 4 years consecutively - add pieces around them.
I think the lack of continuity in our bench is what hurt us the most - maybe the big three play less minutes with a stronger more consistent bench.