Even experts who give Democrats a chance to flip the House recognize that everything would have to go perfectly. Wasserman notes in his report that, despite the recent alterations, he rates only 31 Republican seats at risk of a loss. (Daily Kos Elections puts it a bit higher, with 36 Republican seats potentially threatened.) This means Democrats would have to win virtually every seat in play, and lose none of their own, just to regain a bare majority.
But it takes years to recruit and train candidates who can raise enough money to win a congressional election; you can’t throw it together in a few months. You can see how unprepared Democrats are for this scenario by looking at how many districts won’t have a Democratic candidate at all. Nineteen states have already closed their filing process for House elections, representing 163 Congressional districts. And as Stephen Wolf points out, in 27 of those 163 seats—about one in six—no Democrat will appear on the ballot.
Most of those seats are hopelessly Republican, but not all of them. Six of the districts have a Cook Partisan Voting Index score (a measure of how much more partisan a district is than the median) of “Republican+10” or less. Democrats held two of them, the 3rd and 10th districts in Pennsylvania, as recently as 2010. Illinois’s 16th district, held by Republican Representative Adam Kinzinger, is only R+4, but no Democrat emerged to challenge him. Given their thin margin for error, Democrats need surprises in seats like Kinzinger’s to win the majority. But they cannot get his.
If this pattern continues, dozens more Republicans (in the states where candidates can still file) will see no general-election opposition from Democrats. To give one glaring example, Virginia’s 2nd district, which Mitt Romney won only narrowly in 2012, has an open seat; incumbent Scott Rigell is retiring. But while two Republicans have announced they’re running, no Democrat has declared yet, and filing closes March 31. There’s also no Democrat currently running in Colorado’s 3rd district, an R+5 seat where incumbent Scott Tipton only won 53 percent of the vote in 2012.
Even if most of the Democrat-free districts are deep red, the lack of candidates on the ballot robs the party of capitalizing on a backlash against Trump, or a scandal involving a GOP incumbent. The lack of competition also allows the Republicans to focus more heavily on seats where they’re strongly challenged, preventing the party from being stretched thin financially.
So there's a very good chance that the massive failure of Schultz and the DNC has already assured that the Republicans keep the House no matter how awful Trump and company destroy the GOP, simply because Democrats have already been decimated at the state level. In other words, barely taking the House back in November is about as good as Dems could possibly do, as getting crushed in state and local races for six years and losing districts to gerrymandering means the Republicans have a near-permanent advantage until 2022 at the earliest.
Yes, Trump might cost the GOP the House in 2016, but the path to get there is about as narrow for Dems as Trump has of winning the White House.