Anecdata of one: I got Covid recently, multiple other people around me got Covid recently. None of us got a new booster shot. Not even available yet. Now I don't need it either.
So from my point of view, you can keep your conspiracy theory.
I'll stick to my conspiracy theory if you take a second to look at the data for daily Covid cases, and admit to yourself that it shows no significant spike: https://www.worldometers.info/coronavirus/
Yes, I agree with the general premise, that "as covid becomes more normalized people stop testing / reporting their test results."
But it's hard to reconcile this justification for lack of data, with (a) the current headlines claiming a new surge in cases, and (b) the headlines from two years ago, insisting Covid prevalence was not simply overinflated due to prevalence of testing.
I have never reported any of the 3 times I or anyone in the family have had Covid and that comes out to more than 3 because we didn't all get it at the same time. And that was not just "after", this was even when you had all the 'test centers' everywhere and all that.
I know nobody I know who had Covid that ever reported their case. All just self-tested and stayed at home for the appropriate amount of time. Why stand in line with lots of people that very probably have Covid to get tested and if you don't actually already have Covid, get Covid? Just stay home and isolate and get better.
Again just anecdata of a few but extrapolate that up to a population level and you know why they are now doing the analysis through levels in waste water to get numbers. It's way more accurate.
One thing we can probably agree on is that those centralized test centers were the dumbest idea of the entire pandemic. For the same reasons you state, they always seemed absolutely insane to me. So you think you have Covid? Get in your car and drive to a gathering of a bunch of other people who might have Covid. If you don't have it now, you definitely will after!
Reported tests are almost completely gone compared to past waves, so reported positives will likewise be almost gone. Wastewater data in the US shows a very clear increase, with levels currently at least half of the peak of the previous two waves.
Nobody is even trying to get estimates via testing anymore, and the tests themselves have been growing increasingly unreliable as the virus mutates - the RAT particularly seems to hardly ever turn up true positives via nasal swabs. Look at wastewater COVID RNA load instead: https://biobot.io/data/
So from my point of view, you can keep your conspiracy theory.