Interestingly, if you ignore the political aspects and instead read the Census Bureau’s actual report, you will find that the contention that (a) median income fell under Bush; (b) poverty rose under Bush is mostly a product of the bookends chosen. Both statistics spiked very strongly at the end of Clinton’s reign, owing to the tech bubble, which makes Bush’s years look worse than they actually were.
Long-term, Bush was a wash. Things didn’t get any worse. But they also didn’t get any better. That’s hardly a record to boast about but hardly the worst in history either.