The problem is the zone dictates everything about this program. It's not just that the team is struggling playing it this year, it's that the team is built solely to fit the zone. The personnel brought in is for the zone which means recruiting longer, rangier athletes. Outside of the top 25 types, you don't find many offensively skilled players that also happen to be prototypes for the zone, especially at PG. You find offensive projects and kids with warts that you hope can develop offensive skills.
Then when you add 5th years that don't fit the zone or have the experience, You see how poor the results can be.
And it's harder to find talented kids who also have prototypical zone attributes. When you start missing on them, it exacerbates the problem. When you limit your recruiting base, the problem gets even worse. When you play 100% zone and base everything around it, you have no wiggle room when things go haywire.