The Apollo Program cost a total of $183 billion, inflation adjusted, over 12 years. That's about $15 billion a year. NASA's budget has been for the past 40 years has been $20-$30 billion a year. Even the 'burst funding' wasn't particularly extreme relative to what they now regularly receive. The highest their budget ever was was in 1966 in $57 billion (inflation adjusted) dollars.
To visualize the absurdity of this argument imagine somebody claiming that Uganda funding a space program for $5 billion is receiving some serious financial capital, because that happens to be 10% of their GDP. $5 billion is $5 billion, regardless of your GDP. Ok technically there's PPP calculations, but that doesn't apply to the discussion here.
Obviously percentage of GDP isn't an ideal multiplier for reasons you've mentioned, but then inflation indexed mainly to mass produced common consumer goods tends to significantly underestimate the increase in cost over time of running complex operations involving the world's smartest and most on-demand minds and an almost unfathomably large number of subcontractors. Either way, NASA's overall budget is half that of the 1960s in regular inflation adjusted dollars, and whilst its current research and satellite/ISS maintenance maybe aren't as exciting as the first lunar landing, they're not obviously dramatically lower cost (the %GDP argument gets brought up nearly as often to suggest the Apollo programme wasn't worth it...)
Sat in a lecture theatre with NASA's last chief economist using both metrics earlier this week. Although those slides were looking at cumulative funds spent on Robert Goddard's programme, which was about the size of a largish Series A using the inflation metric or Series B using the GDP adjustment. Whether that's value for money or not depends on whether you're considering being the father of modern rocketry more impressive than sending a handful of moderately complex 16U Cubesats or rideshares or note that the actual rockets were no more sophisticated than some student projects, I guess...
Yet NASA continues to cheerlead for these things. I briefly thought NASA might right their heading under Bridenstine but then at some point he suddenly just did a hard 180. It seems every man has his price. He eventually just turned into another Boeing cheerleader (and his new found rubber stampage is a big part of why that Boeing monstrosity left astronauts stranded on the ISS) and went straight from out of office to a high level advisory gig for some MIC company which is almost certainly just a laundered paycheck.