Mellow, I'll give it fair shot but I'm certainly no expert so ... Fwiw.
I believe it was JFK who lowered rates from90 to 70 not Cater but doesn't matter. Before Reagan you could deduct interest paid on your yacht, your jet and 15000 houses and evry credit card you had. Now you can deduct only your residence and one more. Many other deductions have been closed every time rates were dropped. I don't have the stats to back up my claim but my guess is the effective rates the rich have paid have probably not changed as much as we think.
I have not researched any of this so if someone did and I'm way off base, please correct me. A graph showing effective rates would be cool.