leave out the part where Google arbitrarily and unilaterally decides what constitutes valid, payable traffic. Paying 55% of the ad revenue from a video with 100K views is far and away different than paying 55% of the ad revenue for a video with 100K views but Google has chopped off 90K of those views as invalid traffic
Do you have any evidence of this?
Also, even if this is true, Google does not pay per view. It pays based on the ads that viewers have seen or the ads that the viewer clicks through on. If the viewers have adblock or don't click, then there's no revenue to be shared. If 90% of the viewers use adblock, then 90% of the views won't pay and are "invalid". If anything, this anti-adblock effort would put more money into the hands of the creators.
I am also going to bet that Google is not cutting a break to the advertiser and is charging them the full amount for 100K views.
Do you have any evidence of this?
Actually I know you don't. The advertisers would pay you a lot of money in exchange for such evidence, so if you had any, you wouldn't be talking about it in public.
there would not be reams of articles out there about how content creators are getting fucked over by Google
The ones I've seen are complaining about YouTube failing to promote them or unfair "demonetization" (actually they can still get paid by some advertisers and from direct payments, but it's a lot less than full ads). In that case Google's getting less ad revenue too, so they're not violating the 55%-45% split part of the contract.
about how the content creators cut of the ad revenue has been rapidly declining over the years
It's been 55%-45% as long as I can remember, and I started watching YouTube long before creators could get paid.
We would not see creators resorting to side deals to advertise products and services and begging for Patreon subscriptions.
"Resorting" is a word you're using to appeal to emotion. A more neutral way to say it is "take advantage of".
Regardless of whether Google is being fair to them, it's always in a creator's best interest to increase and diversify income streams. It's also in their best interest to point the finger at Google and complain about how poor they are so it doesn't look like they're doing it to get rich (which they totally are).
By the way, I have never once seen a single person who complained actually show their financial documents. Any honest non-profit that takes donations would happily share that (you can find Wikimedia's here). Strange isn't it?