Last batch of F-35As had a flyaway cost of 102 million apiece, the next is projected to be 96 million each, and they anticipate 85 million each at full production. That is comparable to building any other modern multirole fighter. Pilots are saying it dominating in air to air exercises and in SEAD training has been able to geolocate radiation sources faster than three F-16s could, that fits my definition of "significantly" better especially since it can also take on strike missions against well defended targets that previously only F-117s and B-2s could. A-10s come with an entire logistical footprint that is an expense in itself, continuing to maintain it, and you don't just have an A-10 since you'd need other aircraft for other roles including CAS in contested environments. In the long run it is far more expensive to have planes pigeonholed for a specific role that can't do anything else.
The F-35 will not be dependent on someone on the ground lasing the target, EOTS has a laser that is used for targeting and range finding. EOTS specs iincludes air-to-surface/air-to-air FLIR tracker and air-to-air IRST modes, automatic boresight and aircraft alignment, laser spot tracker, passive and active ranging, and highly accurate geo-coordinate generation to meet precision strike requirements.
Again, most CAS is dropping PGMs which the F-35 can do better than the A-10. I have no idea why you believe an A-10 is unique in ability to fight on it's own.
Stealth isn't relevant for CAS so I have no idea why you're talking about eyeballs. For battlefield awareness no plane in the world touches the F-35, nothing is anywhere close. DAS an see targets moving that a pilot would have never spotted, and sensor fusion would automatically direct other available sensors to gather information to identify and track the threat for the pilot. F-35 sees more than A-10 and can target objectives on the fly much faster.
A-10's cost 18 to 20 million per. Your point? Insurgents hide. It's impossible to spot them from a fast mover flying at 25,000 feet. It's impossible to spot them from a fast mover flying at 50 feet. The pilot is far to busy actually flying the aircraft. If the F-35 slows down it is vulnerable.
The A-10 is low and slow so the pilot is able to spot the bad guys. By himself. Think Sandy missions during the Vietnam War. The A-10 can take a hit from a manpads that will turn an F-35 inside out. The A-10 will fly back to base and the A&P's will get it fixed and back out in the fight.
The 25mm cannon on the F-35 (GAU/22A) has a ammunition capacity of either 182 or 220 rounds depending on which variation it is mounted in. That is roughly 2 to 4 bursts of fire. Figure 4 seconds of firing.
The GAU-8/A, on the other hand, has a capacity of 1174 rounds. Roughly 30 seconds of firing, and it is significantly more capable to boot.
In other words, in a CAS role the F-35 is pathetic. The most accurate form of aerial attack is the gun. The troops on the ground, when in close combat can call an A-10 in and that aircraft can deal with the threat with only the gun thus limiting friendly fire casualties.
The F-35 gets one, maybe two passes and then it's Bingo and time to go home.