The only ones who haven't realized how terrible the SERPs have become are those at Google
I think the ones at Google who are monitoring search are now doing so through a different lens of set of KPI's. What used to be geared to user experience and search quality, is now geared toward user monetization and journey optimization. Google is simply doing all it can to lengthen and monetize each "user journey" (session) as much as possible at the expense of the user experience and quality, ie: delivering quality answers.
You can see it in the docs from the court case as they mention in late 2019, wanting to "extend the user journey" with Shopping widgets, PAA, PAS, Local Service ads, YouTube, ANY other Google property, etc. Basically,
ANYTHING other than clicking off of a Google property via organic competitor, because we ARE competitors to the money users spend and Google wants ALL of that money to flow through itself.
With the HCU knocking out so many large content sites that used MediaVine and other preferred "Google Ad Partners" that effectively hurts their bottom line due to the traffic (and ad click) drop, they are taking the "user journey" even farther. If you use mobile to search, scroll past the second/third swipe page and it's nothing but Youtube and discover with tons of ads scattered throughout. There is no infinite scroll (ie: more than 20-25) of organic search anymore on mobile devices. Well, not for me anyhow. Now it just shows a very non-descript button that asks if you want to see more search results, then rolls right into tons of youtube videos, more ads, etc.
As I recently said: Google has jumped the shark and put profit far higher, likely at the top in it's list of priorities, over the quality search product with targeted users for ads that they built their reputation on. Even advertisers see this as CPC has double/tripled and click quality has dropped.