If the government had to make the software we all had to use, as well as it being free, it would force the government to consider the cost of modifications when they decide in their infinite wisdom that some new tax-break should be created.
Inertia can be good to slow-down knee-jerk politics.
The reality is that governments use taxation as one of their tools to reward certain behaviors and population segments and to discourage/punish others. Simplifying taxation is taking that power away from governments. Why would any government choose to divest itself of those powers?
https://files.taxfoundation.org/20210217111150/Sources-of-ta... from https://taxfoundation.org/us-tax-revenue-2021/
My guess reading this (and my experience growing up in India) is that many countries simply ignore income taxes (if you're the average schmoe with a regular job and salary, you pay taxes. If you are a business person of some sort, you simply accept cash, hide your income and pay no taxes) and the country makes for this shortcoming with a 20% VAT.
There is then a process where people with more complex tax affairs then fill in a government questionnaire on a website which instantly calculates the tax rebate/payment required and adjusts your tax balance.
OR… Intuit can keep shoveling money into campaign funds. We know what it’ll be.