It's somewhat challenging to adjust your offense every year around the players you have...Cal is going after elite talent, and each year that can lead to different skill sets and how players work with each other, hence the need for "tweaks" each year as he figures it out. Other coaches have a system, and recruit to accommodate vs. just taking as many top 20 guys as you can.
Also, let's put a few things in perspective - if Zion was here, we wouldn't be having these questions about Cal...that was a big miss, one you can't come make up for (and we know why Zion isn't here).
The good news is Cal has a solid track record of figuring it out by March, while everyone freaks out in Nov/Dec/Jan/Feb.
You make a really good point about Cal adapting the offense every year. That's often overlooked in these discussions and I'm glad you pointed it out.
Regarding your point about Zion, however, we don't know that Zion would have chosen UK over Clemson if Nike wasn't in the picture. Additionally, we can talk about scenarios "if" Zion was here and how things would be different. But he isn't here, and they aren't different. We didn't land him. Just like we haven't landed 15 other top 5 kids who were offered since 2015. We've landed one of them, and that player was Skal.
So hypothetical perspective is great, but reality is ultimate. We don't have a Zion on the team and we haven't had one since 2015. That's fundamentally the biggest issue right now. UK has to start landing elite freshmen again or land a handful of fringe guys in that second group. Right now, we have that with Maxey and Whitney coming in, but we need another piece or two. We're seeing the limitations of depending on freshmen like Quickley, Green, Richards, Diallo, Washington, Hagans, Herro, etc.