Reagan Elected 1980, market bottomed August 17, 1982 dow bottom about 782. It took years for American Business to overcome the leadership of Jimmy Carter (ie Barak Obama I)
Not to argue but Dr. Art Laffer explained the problem was a delay in putting everything in place. He said the delay caused almost a two year delay in the effects. I don’t remember whether Laffer blamed the Reagan team or himself. I do remember Laffer saying he didn’t push it as he should have done, looking at it in hind sight.
But you’re right on the market not changing that fast. Officially it took longer. I was remembering some business owners I know and a stock broker who all said the change created a great opportunity and those guys all invested pretty quickly.