That is a terrible contract for C's
Ok, let's hear your take.... Is it because he's old, not good, going to get hurt, and could prevent them from signing a better player?
It is way too much and way too many years. Holiday is in his 15th season this year. You can count on 1 hand the number of players that perform at even a reasonably high level that deep into their careers and just because we've seen 3 of them recently (i.e. Lebron, Paul, and Durant this year) doesn't make it the norm. The salary structure even with him off the books was tenuous going forward with Tatum and Brown both on supermax deals and Porzingis still under contract. You then have White that needs to be re-signed. Even with the cap going up, it is a ton of money to spend on your 5th most important player that will be in years 16, 17, 18, and 19 during the life of the extension. Holiday isn't going to be able to play PG at a high level much longer and he isn't big enough or a consistent enough shooter to play off the ball. He has already lost a couple of steps defensively as well (he is still very good, but not elite, and he isn't going to magically get better, only worse).
In 25-26, Tatum, Brown, Jrue, and KP are going to make over 110% of the cap (around 175 million). White is presumably going to get something in the same range as Jrue and KP, which adds another 30 million or so (20% or so of cap). So 205 million or 130% of the cap from just 5 people. Pritchard is another 7.2 million or 4.5% and is the only other guaranteed contract that season (Horford and Hauser are free agents before that year as well).
And Jrue's contract won't be easy to trade because of his age, his diminishing production, and his overall skill set so the team is stuck with him, which means it likely isn't signing White or is trading Brown. The team just isn't financially feasible at those dollars. This is a move that gives good vibes to the team right now, but is a horrid contract going forward. It is basically indefensible.