That is not very accurate. Much of the slave labor was wasted, spent on the war effort or used for stuff that was later bombed.

Also deindustrialisation began in Germany:

Allied plans for German industry after World War II - Wikipedia, the free encyclopedia

The first "level of industry" plan, signed by the Allies on March 29, 1946, stated that German heavy industry was to be lowered to 50% of its 1938 levels by the destruction of 1,500 listed manufacturing plants.^[2] In January 1946 the Allied Control Council set the foundation of the future German economy by putting a cap on German steel production capacity: the maximum allowed was set at about 5,800,000 tons of steel a year, equivalent to 25% of the prewar production level.^[3]

Leading to easily expected effects:

Allied plans for German industry after World War II - Wikipedia, the free encyclopedia

Worries about the sluggish recovery of the European economy (which before the war was driven by the German industrial base) and growing Soviet influence amongst a German population subject to food shortages and economic misery, caused the Joint Chiefs of Staff, and Generals Clay and Marshall to start lobbying the Truman administration for a change of policy.^[14] General Clay stated

"There is no choice between being a communist on 1,500 calories a day and a believer in democracy on a thousand".

However, all that dismantled industry did end up somewhere:

Allied plans for German industry after World War II - Wikipedia, the free encyclopedia

Contrary to common myth, the US did in fact take "reparations"; parts of it by John Gimbel called "plunder and exploitation", directly from Germany. The US for instance took an 8.9% share of dismantled Western German industry.^{[27][not in citation given]}

The Allies also confiscated large amounts of German intellectual property (patents and copyrights, but also trademarks).^[28] Beginning immediately after the German surrender and continuing for the next two years the US pursued a vigorous program to harvest all technological and scientific know-how as well as all patents in Germany. John Gimbel comes to the conclusion, in his book "Science Technology and Reparations: Exploitation and Plunder in Postwar Germany", that the "intellectual reparations" taken by the US (and the UK) amounted to close to $10 billion.^[29][30][31] The US competitors of German firms were encouraged by the occupation authorities to access all records and facilities.^[32]

Anyway, reintegration of Western Germany into the European economy was necessary for the European economy then, just as an end to austerity is necessary for the European economy now.

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