The USAF wants to build up a force of F-35As for dealing with AA/AD and targeting relocatable and transportable things wherever they might be. Longer-range things would be more relevant to Pacific, but are expensive and called bombers.
They are needed, the USAF knows they are needed, but two obstacles must be overcome: Reaching IOC and building a strong force takes a lot of time and money, and changing the bomber/fighter balance takes culture change. And nobody, but nobody, will advocate trading fighter wings today for bombers in 2025-and-later.
The A is not required just to keep the numbers up but to stop the USAF tacair force from falling into a hole (age and capability) from which it cannot be extracted in decades.
And you could up the B/C numbers, but even with optimistic assumptions about positive effects on unit cost, that is going to increase the annual bill for JSF procurement, and that's not a possibility.
The B itself would be in better shape if it was not the most expensive variant, if there was a stronger case for the value of deploying small numbers of aircraft on LHA/LHDs, if there was a stronger case for forward/dispersed basing, and if the Marines were going to replace the Harriers first.