How Europe’s Armies Let Their Guard Down explains how Europe’s armies got old and fat:
One reason Europe has so many soldiers is its strong military labor unions. Unheard of in the U.S. and Britain, these unions trace their history to the end of the 19th century, when disgruntled Dutch soldiers, unhappy about living conditions, banded together into a group called Ons Belang (Our Interests). Similar groups soon sprang up around Western Europe. In the 1970s, European military unions gained sweeping collective-bargaining rights, though they stay out of war-planning and deployment issues.
Military labor unions? What the…?
The average age of a Belgian soldier is 40 — compared with 28 in the U.S. and 29 in the U.K. Most Belgian military personnel can retire at 56 with full pension benefits. The Defense Ministry acknowledges too many of its soldiers are too old, and says it is trying to recruit younger people.
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People who were drafted or signed up in the 1970s and 1980s were guaranteed full employment until retirement. Though it varies from country to country, some European governments, including Belgium, still have that policy today.
Not exactly a 21st-century operation.