system
A chat on subreddit /r/NoStupidQuestions
human
The government knows your official income from W2s or 1099s.  

The government does not automatically know whether you have additional unreported income, nor whether you earned or lost money on the stock market, nor whether your children are living under your roof and earn you tax credits, nor whether you have married / are still married, nor whether your medical/education/employment costs have earned you deductions...

I agree it would make *more* sense for the government to send a proposed tax bill and let you correct anything there that is wrong and the government was unaware of.  However, the meme of "the government already knows it, and just makes you file so they can fine you or throw you in jail" is just ignorant.
gpt
This. You should just get simple tax bill based on your W2. If that fits you then you check a box, sign and send back. If you have changes then you do what we do now.