It's an acknowledgement of 40 years of history and incremental progress backward. When Reagan took office you could support an American family with a high school education and one employed parent. Now, you need two post-graduate degrees to guarantee success in this country. Clinton, Obama, and Biden all had control of Congress during their presidencies. (Obama even had a supermajority for six months.)
They all had the power to make real, meaningful change. They made and broke promises. That's not a matter of opinion. It's a matter of historical fact, and again, a reasonable person has to acknowledge that 40 years of failure to act constitutes policy on the part of Democrats.