I can't tell if you're "/s" but this strikes me as "anyone can download the SMTP RFCs and roll their own mail server" but that's not the same as actually running a mail server due to the monstrous amount of non-functional requirements that have been applied to that space over the years
To the best of my knowledge, the tax filer is responsible for knowing the law, which includes amendments made almost every Congressional session, the court rulings upon both of those things, the judicial meaning of the English words used in all that corpus, and then one can get into the pdfs and their printing and mailing. Or all of those lawyers and enrolled agents can be rented at tax time in order to outsource some of the liability, and thus that's how we end up with the current cesspool of a system we have
Very few taxpayers need to tread into the obscure corners of the tax code, regulations, court cases, and so on.
In fact, the tax forms and accompanying instructions are written at a level that anyone with a high school education should be able to understand. Examples are often included, along with call-outs for "Tips" and "Caution" to highlight key points.
Further, there are dozens of publications that go into more detail and cover probably 90% or more of all the scenarios one would encounter. Pub 17 in particular is a beginning-to-end handbook that covers Form 1040 and the common forms/schedules and the entire filing process, with references to other pubs when appropriate, again all written at a high-school level.
These are available in both PDF and HTML formats. Recall that electronic filing has only been around for a few decades, so prior to that everyone used to fill and file on paper The IRS has long history of providing the necessary instructions to do so at a level accessible to the vast majority of users.
It is also a fact that the tax software providers use these same instructions and publications as the specifications that their software must meet. Literally, they will hold up release of various forms for filing using their software until the IRS finalizes the accompanying form instructions.
To the best of my knowledge, the tax filer is responsible for knowing the law, which includes amendments made almost every Congressional session, the court rulings upon both of those things, the judicial meaning of the English words used in all that corpus, and then one can get into the pdfs and their printing and mailing. Or all of those lawyers and enrolled agents can be rented at tax time in order to outsource some of the liability, and thus that's how we end up with the current cesspool of a system we have