Where is the Democratic bench? Biden is keeping his PAC open. Hillary is back on her speaking tours. I love them both, but I do not want to see either of them running again for Presidency. Same goes for Bernie.
Where is the recruiting? Who will challenge Nunez, Kevin McCarthy, Darrell Issa here in California? These should be easy pickings for Democrats, considering the current high anti-Trump sentiments in the region. If we aren't seeing viable candidates here, I despair of the races in the rust belt and southern states.
There's quite a few...
Tim Kaine (VA),
Cory Booker (NJ, but says no),
Jerry Brown (gov CA),
Julian Castro (mayor - SA-TX) and
Andrew Cuomo (gov NY) could all make a run. Huge speculation that
Elizabeth Warren (MA) will run this time (though she says no). Ditto for
Joe Bidden (Veep/PA) (again he says no, but oddly has a committee)
Bernie Sanders (VT) seems likely (though at some point one age will eventually factor in). It wouldn't surprise me to see
Martin O'Malley or
Terry McAuliffe (Govs of MD & VA, respectively).
..and don't discredit the business/celebs-turned-candidates (since that seems to be the thing now).
Oprah Winfrey, Dwayne Johnson ("the rock"), Mark Zukerberg (FB), Howard Schultz (Starbucks) - all seem laughable but then again so did DJT in early 2016.
Then there are about another dozen who 'might' run. Mostly it will depend on whether their political star waxes or wanes over the next 18 months (e.g. Kamalia Harris (CA), Steve Bollock (gov MT), etc. etc.
Honestly, it's fascinating from a political-spectator standpoint; barring impeachment/resignation/death DJT will almost certainly be the GOP candidate, but there's at least a dozen solid potentials on the Dem's side and they span the spectrum from centrist to socialist and with styles ranging from respected/low-key to firebrand/combative.
The reason we hear so little about it is that very little will happen before the '18 midterms. A few will form exploratory committees, but everyones going to wait to see how the '18 races turn out, what issues flip voters and what kind of candidate might the DNC put their weight behind.