Why else would he be floating proposals he knows can never pass, except to be winning cheap gains from the suckers who don't see it for what it is? A president proposing a huge program like free college for everyone without controlling Congress is basically talking to a wall.

Obama is trying to help the Democratic party with its stagnant voter base problem. The people who would regularly vote Democrat have moved far to the left of the Democratic mainline and are tired of seeing nothing come out of the Democratic party, meaning that they no longer have any motivation to vote for Democrats-- not to say they are voting for Republicans either.

Sure, you're going to say Obamacare came out of the Democracts-- but the left leaning segment of the Democratic base didn't want Obamacare, they wanted single payer, and Obamacare fell horrendously short of that. This election was a wakeup call for the Democrats, and indicated to them that they have lost their base to the more radical members of their party like Elizabeth Warren.

Thus, we see the Democrats attempt to show people that they still have big ideas, because they are incapable of showing people that they have big actions.