I'm not an expert, but I've both played and watched a ton of basketball in my life. Like, a lot.
Basketball is very much a skill sport. If you take 5 random players, you are going find 5 different distinct skill sets. Sometimes, wildly different skill sets. Even if you narrow that to 5 guards or 5 forwards or whatever, you're still going to get quite a variation in skill sets. Players that are true "5 tool" guys (to borrow a baseball term) exist, but are hard to come by - this goes for you coaching your kid's peewee team to Phil Jackson coaching the Lakers. The name of the coaching game (and, in the pros, the GM game) is identifying players that blend well together and fit what you feel confident teaching/running as a coach. "Just find/recruit/sign players who are really good on both ends" isn't really an option. If the NBA ever drops the salary cap, the Lakers or another well-off team might make a run at it. The Dream Team might have come close back in the day, but even they had guys who were there as stoppers, scorers, etc.
That's a long winded way of saying Fran is identifying, recruiting, and playing guys who can score. Defense is a nice bonus, but offense is prioritized. If you are a player who is stronger defensively than offensively, you're going to be further down in the rotation at Iowa than you would find yourself at, say, Virginia.
If you want to see (or demand) great D, Fran's teams are going to drive you nuts. What you're seeing is very intentional and by design. It's no different than walking into Kinnick hoping to see Iowa blitzing 80% of the time or throwing 50 pass attempts. The program has intentionally worked for literally years to be something completely different than that.