I take it that your point is the opposite, but it's still a good one: the Blitz would have gone VERY differently had there been AA guns on every rooftop. It'd get pretty expensive for bombers to plunge into the Channel and pilots thrown into a POW camp.
But the result wouldn't have been AA guns on every rooftop. The UK's capacity to produce AA guns wouldn't have increased. Their economy was already focused entirely on the war. The result would have just been a lack of planning on how to actually make effective use of the resources available.
And there would not have been any advancements on the radars used in "Chain Home", because "Your place got bombed because you didn't defend it well enough, nothing we can do"