I don't necessarily disagree with what you said, but you're not taking a few things into account.

First of all, most people don't think critically, and may not even know how. They consume information provided to them, instinctively trust people they have a social, emotional, or political bond with, are easily persuaded, and rarely question the world around them. This is not surprising or a character flaw—it's deeply engrained in our psyche since birth. Some people learn the skill of critical thinking over time, and are able to do what you said, but this is not common. This ability can even be detrimental if taken too far in the other direction, which is how you get cynicism, misanthropy, conspiracy theories, etc. So it needs to be balanced well to be healthy.

Secondly, psychological manipulation is very effective. We've known this for millennia, but we really understood it in the past century from its military and industrial use. Propaganda and its cousin advertising work very well at large scales precisely because most people are easily persuaded. They don't need to influence everyone, but enough people to buy their product, or to change their thoughts and behavior to align with a particular agenda. So now that we have invented technology that most people can't function without, and made it incredibly addictive, it has become the perfect medium for psyops.

All of these things combined make it extremely difficult for anyone, including skeptics, to get a clear sense of reality. If most of your information sources are corrupt, you need to become an expert information sleuth, and possibly sacrifice modern conveniences and technology for it. Most people, even if capable, are unwilling to make that effort and sacrifice.