I'm not conceding anything, or, if you think I am then you're not listening.
Again, says you. To say "no one cares about additional spending, it's to be expected when your income rises" is complete horseshit. The total dollars you spend absolutely matters. It may not to your life of limos and mansions, but it's a very relevant statistic to most people. You just throw in the "% of GDP" because it's a convenient way to say "we're not spending as much". Proves my point entirely - spending is not important to a Keynesian. If it were, you'd not have to come up with clever ways to make the number look better.
Additionally, the government wouldn't have to change the GDP calculation in order to make it look better. The only thing that matters is total dollars spent, adjusted for inflation (even though inflation is a rigged number as well).