I was initial cadre into the A-10 from the F-4. The F-4 was a multi-role fighter as the F35 aspires to be. Neither the F-4 or the R-35 have the appropriate speed envelop to be successful in the CAS role. The F-16 could not do it either. The Russians built the Frog Foot, SU35 now the SU39 (copy of the A-9 which failed to make the cut). The Russian military doesn't like the Frog Foot any better than the Air Force likes the A-10 and for the same reasons...........not high tech enough! But, the Russians have realized that no other aircraft in the inventory can do the job as well thus they have continued to upgrade the aircraft and build more. The A-10 is not appreciated by the Air Force brass but, to troops putting their lives on the line, it is an answer to their prayers. Their is no aircraft on the drawing boards to replace the A-10. The Army would love to have sole responsibility for this role. The Air Force would gladly give it to them but, they don't want to lose the money this