The tl:dr version is that:
1. The USAF still doesn't really enjoy doing CAS, and
2. The USAF still doesn't really like having to fly slow ugly-ass crates like the A-10, the post-midcentury version of the old Vietnam era "SPAD", the A-1 Skyraider.
As a history buff I can kind of understand why the USAF hates being in the CAS business. It had to fight hard to shake loose from Army control because the Army thought that the best use for aircraft was low over the troops. It's also goddamn dangerous, even moreso with improvements in AAA such as shoulder-fired SAMS as well as longer-range, higher-altitude counterair systems such as the Russian S-400.
That said...upgrades and improvements in the U.S. FA branch have been underwhelming in the past half-century. We're still using legacy systems from the early Cold War and, particularly, the fire support base in the light infantry units (including light mechanized outfits like the Army's Stryker brigades) is dependent on towed gun systems such as the M119A1 and the M777A2 that have some fairly significant issues.
So for the foreseeable future the U.S. Army is going to lean heavily on USAF CAS missions for heavy fire support. The problem appears to be that the USAF is still really unenthused about those missions.
As a former earthpig veterinarian I have a deep emotional fondness for the new SPAD, and so I can't be objective about the USAF's apparent eagerness to 86 it. But perhaps the real problem isn't so much to "Save the SPAD" but to try and avoid sending U.S. infantry to farkle about in places where the need for close air support is essential? Or to rethink the tactical/operational setup so as to provide more fire support in the form of FA fires rather than from the Wild Blue Yonder? OR, as both Sven and Ael mention in the comments, would an entirely new mix of armed drone platforms and improved FA systems be a better solution? Would the USAF be willing to accept an armed Army-controlled CAS drone as an exception to the Key West Agreement..?
