Not so, actually...
Tests were done after the accident that showed that while leaking fuel may have been ignited by the afterburner the flame front's speed was too low to allow the ignition of the fuel further forward. (I think the numbers were flame front speed about 10 metres/second, airflow about 60 metres/second, so you can see what they meant by that.) I think it was taken to be proved by testing that the ignition source for the wing fire was damaged, sparking wiring associated with the landing gear.
No one was going to certify a civil transport airplane that was "unsafe" because of a "naked flame" so that the afterburners were taken to be acceptably safe. Boeing dropped their attempt to build the supersonic aircraft for economic and environmental reasons, I think you will find.
If you remember, there was a sharp rise in the price of oil in 1973, when that put the economics of supersonic flight in doubt. Concorde had been designed when fuel was still cheap, since it burned lots of the stuff!
Then there were tests done using a B-70 to see what the sonic boom would be like over the central United States, when millions of dollars in damage was done. That meant we could forget going supersonic from New York to LA, for instance, so that the market for a Boeing supersonic airliner should be much smaller that if that were allowable.
Braniff had already been operating Concorde between Texas and New Żork subsonic and failing to make that pay. A conventional subsonic airliner was much cheaper to operate than a supersonic airliner flown subsonic, no surprise really.
Concorde was a wonderful technical accomplishment but it was damaged by economics to the point where it just didn't pay to continue flying it, I think. It was not grounded due to safety, having been successfully modified post-crash. I think we could put it in that corner of aviation with the Graf Zeppelin, the Spruce Goose and the Saunders-Roe Princess, technical successes but economic failures.