I mean, in hindsight the OP was sort of right. But it wasn't until after the start of the year 2020, and the cause was the coronavirus, a force majeure. Otherwise the economy would've kept chugging along slowly but not so slow as to make for a recession.
The point of Republican tax cuts is that the money that doesn't get taken from a corporation or business it can invest, which in the long term is a smarter use of that money than whatever the government would've spent it on. That is to say, the government refrains from "eating its seed" so that it can be sown for the future instead.
This of course assumes an economy interested in investment. But it appears that this does in fact describe the US. Per one source, investment as percentage of GDP was, at the end of 2019, at levels comparable to the gross average from 1947 to the present.
Investment is probably not easy to measure. When an investment will eventually bear fruit, and to what degree, or if at all, will obviously vary a lot between one industry/company and another. But the US faces steep international competition on all fronts so merely maintaining a GDP of 21 Trillion, much more growing this figure by a couple hundred billion dollars a year, would naturally be quite the feat that'd require no small sum of short-term sacrifice to pull off.