Are Service-Based Economies Disadvantaged During War?

The natural progression for national economies over the past century seems to be agrarian -> industrial/product -> services. However, are service-based economies inherently disadvantaged when it comes to fighting wars?

For instance, Margaret Thatcher's controversial policies in the 80s and 90s that violently shifted Great Britain away from manufacturing and towards services resulted in the decay of their domestic military-industrial industry, which used to be at the bleeding edge when it came to naval engineering and aviation, not to mention armored vehicles and artillery.

While the US seems to be the sole service-based economy that still pumps out war machines in high quantities and quality, that owes to the sheer size of their MIC and their ridiculous defense spending. 
 

However, an overlooked fact is that when war begins and mass mobilization/wartime production starts, service-based sectors cannot be easily repurposed to wartime production. For instance, automobile manufacturers can be repurposed to create light armored vehicles or replacement parts for various land-based platforms and shipbuilders can be tasked to construct warships ( dual-purpose civilian and military shipyards are commonplace in highly developed industrial economies such as PRC, Korea or Japan). A law firm, investment bank or dating app startup (high end service equivalents to restaraunts, barbershops or nail salons) would be practically useless during a war.