Great question. He failed for two reasons.
First, Congress resisted it. And that will be one of his biggest challenges this time. But at least this time, many Republican Congressmen are Trump supporters. At the time, many Republicans were NeoCons like Liz Cheney, who supported a big powerful federal government.
Republicans and Democrats had policy differences in 2016, but for the most part both parties wanted the federal government to have a lot of power. That power emanates from "the Swamp", who can investigate, prosecute, regulate, and tax people (using fees and penalties rather than actual taxes) without Congressional approval.
For example, in 2018 Congress passed a veto proof bipartisan spending bill adding billions of dollars to our government's annual spending. Trump said he was signing it because Congress wanted it.
The NeoCons are gone, but there is still the challenge that even if every Congressional Republican wants to cut spending, they don't want it to impact their districts.
Secondly, Trump had no idea how to get things done. He brought in many "competent" executives that did not share his vision regarding the size of government. Remember, Trump went from a company to running a country and he had a lot to learn about the differences. This time he has picked people that share his vision (more or less).
However, it remains to be seen if he can pull it off. I had a previous HHS Secretary (under Reagan) and previous governor of Indiana on one of my boards and he made clear how hard it is to effect change in Washington. In hindsight, he should have fired most of the senior bureaucrats that did not move quickly to reform the agency and staffed it with new management committed to his goals. Very few people are prepared to deal with the "power of the Swamp".
Will Trump succeed, who knows. But I think he will try, and I think his nominees seem much more aligned with his goals. However, if they don't purge their agencies of many senior bureaucrats, you can expect they will slow walk every attempt to reform them.
