Thing is, back then as now, that rate only screwed people who were getting actual wages or salaries, and there were many ways to shelter or defer compensation for senior executives. So, the people who it screwed weren't the fat cats with low friends in high places (Like Congress), they were the higher-end middle management and master tradesmen like plumbers and electricians.
The only 'Policy goals' those rates achieved was the entirely unintended consequence of wiping out sole-practitioner doctors who found they could only prosper in the ever-harsher litigation, tax, and insurance driven game by becoming part-owners of elaborate interlocking clinical LLC arrangements with business managers before doing any actual medicine...that, and fostering an incredibly active under-the-table economy in skilled trades, since more and more work was getting done off-book into the late 70s, when the top tax rates came down from the 70% they were at until even that recently.