> This is still a lot more work than in many countries, and you still need to either fill in a paper 1040 (plus state taxes where appropriate, and some of those (cough CA) are far from simple), use tax prep software, or someone like H&R Block.

Not in my experience. The online options the IRS provides free of charge is pretty easy, and many states have similarly simple online forms for free.

https://www.irs.gov/e-file-providers/free-file-fillable-form...

Although I do not dispute other countries do have it easier, and do it better than the US.