Regardless of whether they stay below next season they've already saved $325 million in combined salary and luxury tax this season.
To me, every dollar an owner isn't spending in luxury tax are dollars they can invest in players (and taxes) when they are going for a title and that's going to be reinvested for a true championship run.
As you note, if they re-sign Vooch to a long-term contract next season @ his current $21 million, they would only have $10 million to sign another player.
But some think it's possible that instead of re-signing the 35 year old Vooch to a long term contract, Stevens might want to use his $21 million plus the $10 million you mentioned, and use that $30 million to sign a younger, better, longer term solution at Center.
While $30 million might not be much in today's NBA, that amount could still attract a decent player - and they'd probably work a contract that is more back loaded to pay AFTER the re-set, rather than front load it for next season. So maybe this is a player in the $40 million a year category.
So no, that's not the $60 million level for Tatum and Brown but still something more than a bench player salary.
So it may not be a done deal that Vooch will be re-signed, and they might be looking to add a C in the $30 million salary range - while still avoiding the luxury tax.
All of which is amazing given that we are contenders this season (kindof) and can be even better next season, without going over the luxury tax - which while it's a false ceiling, I think we all do know it's real money to ownership and does impact their choices on where and when to upgrade.
This is all crazy as no one would have imagined they could have done all of this and remained contenders, but indeed they have!
Here's a more detailed breakdown
On how the Celtics managed to get under the tax, what they get from it, and a creative plan to remain below it.
www.thirdapron.com