They didn't decide the war, to be sure. But I think there's a compelling argument to be made that they considerably shortened it.

The German industrial war machine in fact remained surprisingly effective in the face of allied bombing until early 1945 [1] when the scale of the bombing finally became overwhelming. But by this time the Germans were going to lose anyway because they couldn’t continue to handle devastating tactical attrition on two fronts. Prior to 1945, German manufacturing was more constrained by the (non) availability of critical resources (coal and steel) than affected by allied bombing [2]. The bombing also failed to decisively impact German civilian morale until very late in the war [3].

However, bombing did force the Germans to prioritise air defence of their heartlands over tactical air operations against allied ground forces, so that German ground forces and their logistics chains operated under punishingly hostile skies from D-Day onwards.

[1] https://www.penguin.co.uk/books/53742/the-bombing-war/

[2] https://en.wikipedia.org/wiki/The_Wages_of_Destruction

[3] https://www.amazon.co.uk/German-War-Nation-Under-1939-45-x/d...

[EDIT - reworded for clarity and additional detail]

The bombing operations forced Germany not only to use its planes defensively instead of tactically against the Soviet Union (and build high altitude fighters to begin with), but also forced them to spend an enormous amount of resources on anti-air guns, bunkers for civilians, military assets and manufacturing, radar systems, and what not, all of which could have being spend.

As especially the USA's industrial output was much larger than Germany's, bombers might still have been a good investment, even if it didn't actually reduce Germany's industrial capacity, because it did reduce its capacity to wage ground war.

EDIT: Also, even if Germany's industrial output did grow during WWII, it still tied up an enormous amount of resources: "The Allied bombing campaign also tied up valuable manpower, with Albert Speer (Germany's Minister of Armaments) estimating that in the summer of 1944 between 200,000 and 300,000 men were permanently employed in repairing oil installations and placing oil production underground. "

https://en.wikipedia.org/wiki/Economy_of_Nazi_Germany#Wartim...

-I don't think that argument stands up to scrutiny; Dresden (to take but the latest and most infamous example of WWII fire bombing) basically happened after Germany's ability to put up a fight had been crushed.

Most notably, in the 2nd half of 1944 they effectively lost the oil imports from Romania; at the same time, they were fighting on three fronts - with the Allies coming up through Italy and crossing the Channel, the Soviets from the east. They had to do an awful lot more with an awful lot less.

Granted, it could be argued that obliterating an important railroad junction like Dresden made logistics (even) harder for the Germans - but again, at that late point in the war it probably didn't matter much.