You can't blame President Trump. If Bitch and Ryan had wanted a wall, there would have been a wall.
Trump could have asked Ryan and McConnell for a funding commitment in November of 2016. Had it not been forthcoming, he should have declared an emergency then, when the republicans had a majority in both houses.
He may yet build, if he can avoid a veto override, but you can’t relieve him of responsibility. He made the promise a hundred times and he will sink or swim on that basis.