That (bolded) statement is simply untrue. Allied bombing absolutely crippled Germany's petroleum output (both natural and synthetic fuels) making victory pretty much an impossibility for the Germans. Also, fighter plane production was greatly affected. So much so that the Germans had to break-up their centralized manufacturing effort and disperse it far and wide. If "neither worked" then why did the Luftwaffe pull a substantial portion of its Eastern Front fighter force and reassign it to France, western Germany, Holland, and Belgium? I'll answer that. It was a desperate attempt to stem the immense destruction of their manufacturing output. It was so vital that German fighter pilots were awarded two, and then later three air kills for every bomber they brought down.
Also, the hordes of bombers devastating Germany forced the Luftwaffe to focus on killing the American B-17 and B-24 heavy bombers (and British Avro Lancasters and Halifax heavy bombers at night). Meanwhile, the USA fighter forces were directed to perform dangerous low-level attacks on the German transportation system (railroads, truck convoys, barge traffic, coastal sea traffic, etc), Luftwaffe fighter bases and all other targets of opportunity. The German's fighter forces were unable to cope with this two-pronged Allied attack as they were stretched too thin. The Luftwaffe rapidly lost the battle of attrition as 1944 came to a close. By D-Day the German fuel supply had been reduced to only about 10% of what was required to remain combat effective. Fuel guzzling heavy Panzers were often abandoned as fuel supplies dried up on both fronts. Also, the huge strategic bombing effort drew vast resources away from the Eastern Front in a very successful effort to assist advancing Russian forces. So the statement "neither worked" is quite incorrect.