no, the irs is not "avoiding code complexity" by those limits. the limits are purely chosen by intuit and irs "goals".
first, irs already have how to calculate all of your tax. period. they do that since the 50s and let you guess if you got it right.
then the limits exclude everyone who is the market for intuit, not some complex to code form. have a job were paying $200 is nothing? keep payinh intuit. have some stocks in your retirement plan? keep paying intuit. are too poor that you would rather no bother paying taxes? heres free file from the irs!