The Army can and does use more creative staffing models for pilots than the USN/USMC/USAF.

That's because Army aviation is a supporting function, they can have lots of warrants or people like in your example who are not on track for future high leadership positions. Most army pilots can stay in the cockpit or pretty close to it most of the time.

For the USAF aviation is the main event, pilots are at the pointy end, so they need lots of those pilots taking their expertise and experience to staff and leadership roles at all levels of the enterprise.

The USN is not a coast guard, it is a long-range blue water force and aviation is it's primary power-projection tool. Same needs as the AF for experienced pilots in staff and leadership.

For USMC, aviation is one of three fundamental pillars of their fighting model (air, ground, logistics), so their pilot staffing model is about the same as the USN. Can't have one of the pillars under-represented in the senior-officer/staff realm.

Also, dose of reality, USN/USAF/USMC pilot slots are used as a de facto recruiting and retention tool for the officer ranks. Didn't start out that way intentionally but that's where it wound up. If they switched to warrant/enlisted pilots it would mess up officer recruiting (the ones they really want would go do something else, or be stuck, possibly quite happily, in enlisted/warrant/LDO ranks). Those three services will let you have your fun but then they expect you to contribute in different ways as you get more senior.