It will never happen in the US. Congress has filled the tax code with thousands of deductions, credits, exceptions, and special conditions, either to reward political constituencies, or to reward behavior that is trendy or socially acceptable. The IRS doesn't know if you bought an electric car, or installed an efficient air conditioner in your house. They don't know if your house is your "main home". For small businesses, the IRS doesn't know what equipment they bought or what customers paid in cash, and whether you want to use standard depreciation, bonus depreciation, section 179, or a safe harbor.
Before income taxes could ever be automated, there would have to be a significant and painful structural overhaul and simplification of the tax code, that would impact every possible taxpayer in some small or large way, that would lead to screaming from angry voters everywhere. Right now the tax code is too complicated and too full of special rules that an apply to limited groups of taxpayers who do the "right" thing according to some congressperson from 40 years ago.
