The post isn't really about Danny Ainge, it's about the type and volume of decisions that need to be made to keep any team over the salary cap for 18 years, which I find to be a funny historical footnote.
If you want to talk about Ainge and the Blazers I would throw a couple of counters out there:
No GM goes over a decade in their job without making some mistakes and Ainge has certainly made some
There's a huge amount of luck involved in how a GM is viewed, especially when dealing with draft picks and injuries
The Celtics didn't get fleeced in the LaFrentz/Roy - Ratliff trade nearly as much as you say because the trade worked out exactly as both teams hoped it would. The point of the post is about the salary cap and the Celtics had, in an era before the current CBA where long contracts were regularly traded for expirings and picks, just spent the past decade in cap hell induced mediocrity. The Blazers bought a pick because they could afford to. The Celtics sold a pick because they felt they had to. The Ratliff contract that they traded for was a calculated gamble that paid off for both teams; it was a piece Ainge vocally wanted. You got Roy but the Celtics don't get Garnett if they have LaFrentz instead of Ratliff. It's easy to say they sold the rights to Roy but they sold the rights to Roy so they could take a shot big game hunting and it turned out they bagged the biggest game available.
Then it comes down to luck. In the end, would you rather have had Brandon Roy and Raef LaFrentz or Rajon Rondo, who Ainge came back into the draft to get instead, and Theo Ratliff? Roy was wonderful but we all know where that ended. Rondo starts on a title winner, makes four all stars, was the best player in multiple playoff series, then gets traded for what amounts to a 1st, 3 2nds, and a rotation player. In the end all of Ainge's gambles that year paid off and that luck is part of what defines every GM's career.
On Durant/Oden, Ainge was as open as you can be when talking about someone else's players that he would have taken Durant. He was that way up to and past the draft. He may have been one of the very few left but it never really changed. On our sub we did "Book Club" with Peter May's Top of the World where he writes at the time that even after the tournament Ainge was leaning towards Durant. Regardless, it's not the point in the context of the salary cap. If the Celtics had taken Oden the same thing would have occurred where they trade Pierce and go under the cap after 12 years which isn't nearly as unique as being over for 18, which is what I find interesting.
A lot of people wanted Ainge fired (and Rivers too) prior to the KG trade, which only happened because one of his best friends and former teammate Kevin McHale was still the GM of the Timberwolves and wanted to help out his buddy.
This is just blatant revisionist history. A lot of people wanted Rivers fired but not nearly as many targeted Ainge. The Wolves didn't trade Garnett because McHale is Ainge's friend. They traded Garnett because the T-Wolves weren't going anywhere and the Celtics had traded for and developed enough young talent where they could swing trades for both Ray Allen and KG at once. If Al Jefferson doesn't get hurt in Minnesota then they traded KG for a 23 year old burgeoning all star and what would become the sixth pick in a future draft. If they had traded KG for a young future all star and Steph Curry (instead they picked Flynn and Rubio back-to-back) would people still say the trade was about "helping out a friend" or would McHale be viewed very differently? Luck is a real thing.