I think that often, there is some common sense consideration of tax policy before enacting or changing tax rules. One example was the 1954 decision to enact IRC section 174 to allow for expensing of R&D expenditures. That simplified the law to avoid uncertainties and taxpayer/IRS disputes on the life for amortization purposes of these expenses. It also incentivized these expenditures that also benefit the economy through new technologies to improve our lives. I’m sure we can find more recent examples too.
Of course, before leaving my example, I should note that the 2017 Tax Cuts and Jobs Act modified the R&D expensing rule starting after 2021 to require R&D expenditures to be capitalized each year and amortized over 5 years (15 years for foreign R&D). That’s an odd provision for a piece of legislation intended to improve international competitiveness of our tax system when most other countries have research incentives in their tax law, but oh well. (I think we’ll see this rule forever postponed and hopefully repealed at some point to go back to expensing.)