This headline is exactly wrong. The Dems taking the House is the best thing that can happen to Trump. When the GOP controls all 3 branches of government, there is no escaping blame when things go bad. Right now, the economy is roaring. This huge upturn corresponded directly with the Trump election (correlation vs. causation of course) but there is no denying that the economy is/was great up until the Dems took the House. So, Trump now has a ready made scapegoat for any downturn that may occur between now and election 2020.
Even better for Trump/GOP, it is now possible to blame everything on the Democrats in the House, everything from legislation not passing, to immigration, to the economy. Look at the approval ratings for any party that controls all 3 branches, they are terrible because the party will always fail to deliver on their campaign promises. It ALWAYS leads to voter apathy and tuning out of politics in general. You want a prediction? MSNBC ratings will fall greatly over the next 2 years as their duped voters get disillusioned with the lack of any meaningful changes brought about by the House Dems. There will be obstruction, meaningless investigations, and nothing to show for their control legislatively in 2020.
Let's be totally honest. Government is always dysfunctional, leading to over promising and under delivering. Leading up to 2018, the Dems have achieved max interest in politics as they mistakenly trusted that voting Dem will lead to change (it won't and we all know it won't). Meanwhile, the GOP finally has someone to blame for their complete lack of success in implementing the Trump agenda outside of a tax cut and Trump's executive actions.
So, not only does Trump have his scapegoat that he can pound in TV interviews (hard to do when it is his own party like Ryan), but he will likely even get one more SC Justice given the GOP retained the Senate. After the Dem debacle with Kavanaugh, they can't play the 'sex offender' card anymore and I suspect Trump to nominate and ram through a Justice to the right of Lord Palpatine. Unless the Dems can figure out a way to play Weekend at Bernie's with RBG, they are losing another seat.
If the GOP would have won the House, the Dems would have had a 50/50 shot at beating Trump in 2020, and even much higher if an economic downturn would have occurred. Now, Trump 2020 is all but assured and an economic downturn now will cement the impression that Dems are bad for the economy for generations to come. That, paired with the potential of Trump getting another SC Justice is the best thing any conservative could have asked for in this election.