What I'm asking is how did Europe continue warring so shortly after a war that was as devastating as the Thirty Years War was for Europe. The 30YW ravaged Europe in a very dramatic way, with large swathes of Europe being laid low, and many considering it one of the most destructive European wars in history (shamelessly taken from Wikipedia, though I've heard the same claims from former history profs). For example, literally the same year that the Peace of Westphalia brought an end to the Thirty Years War, Sweden would begin its invasion of the Polish-Lithuanian Commonwealth, which is crazy given that Sweden was one of the major players in the 30 Years War (Granted, war didn't ever reach their doorstep as far as I understand).
Business as usual in what way? Because Europe really didn't just keep trucking along. The 30 Years War more or less reworked the political landscape of Europe and the way diplomacy was run. You mention the Swedes invading Poland and I think that's a great example of how things changed. At the outset of the war, one of the biggest worries of the Hapsburgs was the army of Denmark (which turned out to be a paper tiger). The Swedish army wasn't even considered. When the Swedes intervened their army was discovered to be potent and capable, but it was "thin." Sweden's army was maintained by conscription in a very thinly populated land. That Sweden was able to invade Poland after the Thirty Years War is related to its relatively untouched landscape and the fact that everyone around Sweden had been knocked down a peg. After the war, who around Sweden was going to be able to stop them, when you consider that they had an experienced army and were probably the most densely populated single polity in their region?
Other things changed around the era, too, which reflects the general upheaval at the end of the Thirty Years War. The Roundheads in the United Kingdom finally put the finishing touches on King Charles' Cavaliers, leading to years of Cromwell's leadership and the execution of Charles I. The Fronde began in France, which crippled the French kingdom for five years and eventually led to Louis XIV refining absolutism to his nobility's detriment. Spain was financially exhausted and had no choice but to let Portugal go when it revolted. The individual German princelings and kings were allowed to conduct their own foreign policy (which would fatally fracture the Holy Roman Empire as a united entity).
It's tempting to describe the German heartland as a desert, but in some ways that's what it was. The power centers in Europe moved towards France, Vienna, and-- a little late-- London. Europe didn't just keep going: it was dramatically transformed. What you're really seeing is that previously "second-rate" powers taking advantage of the situation to try to transform themselves into first-rate powers.