The only way to reduce the pain instead of just shifting it around would be to massively simplify the source of truth - tax codes and laws.
I have to imagine government workers are already writing software to identify if we’ve all implemented it correctly, when the could have just given us the code/api up front.
Because of the jurisdiction issue, even if each local (and for each location all relevant governmental tax authorities) had a clear API, interacting with them all, and dealing with the interactions between them recursively, is itself a large problem.
And from what I've seen from smaller jurisdictions, the automation software is all about simplifying a human-in-loop workflow rather than full machine-driven rules.
I could imagine a world where the IRS ran the tax software for every taxing entity in the US. Each jurisdiction would have to configure their specs or potentially even codify the business logic. International would likely be tricky but it's similar to what is being done with ACH and other banking systems that are slowing moving to international. So, it's not impossible there's just not much of a push for it.
Nay. Shifting pain from thousands of projects to a single org obviously reduces overall impact.
If you believe the statistics on literacy and multi-lingualism, it's a tossup as to whether Chinese or legalese is more widely understood.
Some tax regulations were considered illegal by higher authorities, but that won't stop a tax auditor in a local level charging them and potentially closing down your business.