While Democrats are certain to lose a lot of seats in November, it's entirely possible they'll hang onto the House majority, and very likely they'll retain a majority of the Senate but much farther from 60 votes. In that case, they'll have little chance to break filibusters, but will still be able to pass some kinds of legislation, such as bills to promote employment, through budget reconciliation, which can't be filibustered. But they've decided not to pass a budget and, hence, not to give themselves that opportunity:

Recognizing that Democrats would be reluctant to record “yes” votes for a budget that would augment the deficit, the House leadership opted to deem as passed a “budget enforcement resolution” instead, just before the July 4 recess. While the distinction between an enforcement resolution and a full budget is largely technical, there is one crucial difference: Under the enforcement resolution, Democrats can no longer use a parliamentary tactic known as budget reconciliation next year — a process Democrats had hoped might allow them to pass key pieces of legislation, such as a jobs bill, with 51 votes in the Senate, as opposed to the usual 60 needed to overcome a filibuster.
Under the arcane rules of the Senate, budget reconciliation can only be used if it was written into the budget rules passed the previous year. With no full budget, there can be no reconciliation.

Nice work, House Democrats.