If it were up to me, this is what I would do....
The government should authorize and create a low volume assembly/supply chain capable of making 12 new A-10s every year. I am assuming this will take about 4 years to become established to the point where new A-10s in their latest configuration can start rolling off the assembly line, or produce the equivalent in spare parts. That means 120 new A-10s can be produced every 10 years, or the equivalent in spare parts. This low volume assembly/supply chain should be maintained indefinitely, keeping a new supply available and rotating out aging airframes every 20-30 years depending on how large the fleet needs to be.
Once we have the ability to manufacture new A-10s and all the parts as needed, the actual production can be stepped up or stepped down as needed, as long as the assembly/supply chain is maintained. Maybe after 20 years and a resupplied fleet, we step down to 6 per year instead of 12, or maybe we need to step up to 18 per year to resupply or grow the fleet. We can keep it like this as long as we don't shut down the line. This means we keep the best CAS airframe in our military arsenal for ever.
We use aircraft carriers in our navy, and we deploy other vessels to protect them. We are currently doing the same thing with the A-10, and now we are using the A-10 as forward observers to help direct other aircraft to their targets more precisely. The A-10 is not obsolete. It is adaptable.