You make some fair statements, but I think it's a leap in assumptions and logic to say we're tapped out with Tad. Coaches are learning and evolving, and I don't think he's reached his ceiling...but that's just difference of opinion I guess.
Rankings shouldn't be so important - they come as a product of statement wins. If you can consistently win 20 games a year, to me, that's equivalent of being a borderline top-25 team (I KNOW there can be holes poked in that statement, but just let me have that statement; it's not egregious).
How do we turn the corner and elevate into more dominant presence? Well, this question does go back to your statement about Tad being tapped out. Without having seen more from him, sure, he's not the guy to make us a top 10 team overnight. However, good luck finding that coach...they are rare and will cost you a lot of money, and you will likely strike out on someone who seems like a slam dunk hire before you get a guy that is it. Other options: We need to develop another player with the talent to go NBA lottery, or just get a few one/two-and-dones.
Many people say exactly what you say - drive/dribble penetration. To me, yes, but that simplifies the main theme. You beat the zone with good ball movement. Dribble penetration moves the ball into the middle of the zone, forcing defenders to react. Once you get defenders reacting to you, you can move the ball around to the person that is free. Get the defense reacting though is the main key imo. I have said for a long time that Arvydas Sabonis would have been the best person ever to beat a zone if he played his prime in the US. Instead of penetrate with the dribble, do it with the pass to a big in the high post. He can shoot a wide open mid-range if middle man doesn't help. If someone does help, move shooters around to get free and pass ball off.
I never played serious bball though, never had a coach even, so would be interested to see how others would attack it.