But few people actually do because it is a painful experience. The IRS' documentation isn't actually bad, it is just that the tax system itself is incredibly (and needlessly) complicated.

For example, you'd need to hand-enter every stock trade (even automated re-investments) even though your broker likely already electronically sent this information to the IRS. Using a digital solution they can often log into your broker and auto-import everything.

For how under-budget the IRS is and how bad the tax system is, they do ok, but the whole thing needs a massive overhaul but there is money in politics keeping it bad in order to profit private companies (plus there's a certain demographic that "hating taxes" is a political position that needs to be kept up with, essentially self-reinforcing-itself).