The way the luxury tax is set up, it's important to stay under the tax until you're ready to go all-in. When you do go all-in, you have to manage your long term cap so that you're not in the luxury tax for too many years in a row.
Spending a lot of money and going into the luxury tax year after year severely limits your options for building a roster.
This is the kind of nuance that Felger and Mazz never bother to discover, let alone articulate.
Much easier to dump on the Celtics because their audience tends to skew towards the Sox, Bruins, and Patriots, and not like basketball so much.
When will be the “right” time to go all in?
As long as you have 9 players on rookie deals (that number seems to be constant the last few seasons and going fwd) why not wait and avoid the tax? It’s the same thing year after year
That's a fair question.
I think Ryan Bernardoni has done good writing talking about this exact question over at his site
https://www.dangerc.art/I think the short answer is you go all-in when you think that the doing so will make a big enough difference that it will boost your title odds significantly. I think it's also a matter of keeping your eye on your long term cap sheet so that you manage your ability to maintain / add assets to your supporting cast.
If you go all-in one year but then you lose a few guys in free agency and don't have the ability to replace them, you've kind of undermined your ability to compete the next year. Unless you're in a roster situation where you NEED to put all your chips in for the current season, it makes more sense to have multiple relatively lesser opportunities to make a title run than to maximize a single year at the expense of the following year or two.
Hard to really put accurate or scientific numbers on this, but if you look at your team and you think you maybe have a 5-10% chance of winning the title, and maybe a 20% chance of making the Finals, does it make sense to leverage your cap space and assets to increase your odds to 15%? 20%? What if you know that doing so will decrease your odds the following year to 1-5%?
Right now the Celts are a second tier contender. Their stars are not in the 28-33 window of "gotta win now before you lose your fastball" range. It is reasonable to expect that Tatum and Brown are going to be even better 2-3 years from now than they are this season. Meanwhile, you've got teams like the Lakers, Nets, and Clippers who are leveraged much more for the near term, and whose stars are more experienced, older, more established, and generally better than Tatum / Brown.
Does it make sense to go all-in right now? Probably not. I doubt that doing whatever it takes to maximize this roster would change the Celts from a second tier / dark horse team to one of the favorites. Given that, it probably makes more sense to try to maximize the team's ability to compete 2-3 years from now when Tatum and Brown are nearing their apex and some of the younger guys on the roster are more seasoned.
With all of that said, the counter is that Kemba probably only has a couple years left at his current level, if that. He's only under contract for another year or two, anyway. Then you have Marcus Smart, who is only under contract for a couple more years and might also age somewhat quickly due to all of the wear and tear he's put on his body over the years, even though he's still relatively young.
Also, you've still an elite build-around player in Tatum who has shown he can carry a team in the playoffs, even if he isn't at that LeBron / Durant level yet, and you've got a very good second star in Brown. It's still a very talented core that has shown the ability to go deep in the playoffs. It doesn't make sense to say "Well we're not all-in this year so let's go super young and not even try to compete this season." Because you never know what might happen in the playoffs. Maybe Tatum gets super hot at just the right time and the Celts get lucky. You need to leave that option open even if you're not all-in for the current season.
My belief is that it makes sense to mostly keep the powder dry while still showing Tatum and Brown that you're trying to put a competitive supporting cast around them without compromising the ability to improve the roster in the future. Both guys are still at a stage in their career where they're proving how good they can be, rather than feeling that desperation of "I've got to win to secure my legacy and if I can't do it here I need to go elsewhere."
We will doubtless reach that point soon enough, and Ainge and co. need to be ready to be aggressive when that happens. Look at what Milwaukee did recently to convince Giannis they were serious and get him to sign an extension.