Man: If the rich paid their fair share we wouldn't have to kill him...
Elephant: It's just a haircut.
…so, it’s unproven both ways. The growth happened after the tax cut, with no clear cause-and-effect. So, from the perspective of 2006, it looked as if the tax cuts may have done a lot of good, little good, or no good, if absolute proof is the standard.
Now, we know the economy tanked in spectacular fashion under the same low rates. Changes the debate a bit.
Have you looked for a breakdown of which part of the tax cut was more beneficial? I’m betting the money put into the pockets of middle-class consumers was a bigger boost than the cut for the top. With more economic activity, businesses can earn their profits from consumers instead of asking for ever larger tax cuts.