The A-10 would have been perfect for Vietnam, as it was basically an armored Skyraider with better payload that could bust the ZSU-23-4 mobile radar-guided AAA platform. We still would have lost them to AAA and MANPADs, but they would have had better on-station time and munitions carriage depth to help out Troops In-Contact compared to A-1s and AH-1s.
By the time we started YA-10 test flights, it was already obsolete though. 1970s-era Soviet SAMs and Radar-guided AAA made the A-10 a death trap/strafe rag. It would have been better to put the money into SLEP’ing the F-111F and EF-111A. Getting PAVE Tac capability into the F-111D and throttling systems development and fielding of LANTIRN onto F-16C Block 40 and F-15E sooner, so they could go tank-plinking at night ahead of the FLOT and deeper into the interdiction kill boxes.
A-10A and OA-10A had to be grounded during ODS due to attrition and fatalities. Too slow, not very survivable. It was fine as long as it stayed close to the FLOT for the armored units, but got into deep doo doo when it tried to do armed recon and limited interdiction out further. Was a strafe rag for mobile SAMs and AAA in those spaces.
In the end, we wasted thousands upon thousands of seats that could have been better-allocated for TAC AIR platforms that actually have use in the Air Tasking Order, namely later blocks F-16C and F-15E.
They spent billions on SLEP’ing A-10Cs, which have no mission in the modern ATO.
