A nation's war effort is more than how many fighter planes it produces in a year. Even if it were, for those fighter planes to be useful, they need to work reliably (have acceptable production quality) and they need gasoline, oil, ammunition, pilots, spare parts, mechanics, transportation, food, facilities, housing for support staff, and coordination. If a nation lacks some of those aspects, it doesn't matter how many fighters are counted as produced.
What bombing did to Germany was to greatly harm most of those aspects. To conclude from a few statistics (production numbers for aircraft, guns, and tanks, for example) that bombing wasn't effective is to leave uncounted a large number of other vital factors.