I'm generally not a Trump fan but I do agree that things that affect the entire country should be handled in a centralized manner. Trump is stating that he will dictate when the States can open up again. Many governors, Dems and Reps, are fighting that saying that they have the power, not the President.
Of course, the Constitution puts a great deal of power in the hands of each State. But I agree with him on how these Governors want to dictate how each of their fiefdoms work. So to get anything done, you currently have to appease 50 different Governors. China would never accept that. If they want to get something done on a national level, it is dictated from the top.
The same applies to other national issues such as elections. Having 50 separate "national" elections just doesn't make sense when a President is being chosen to represent the entire country. Have one national election and that is it.
Many times I do not agree with Trump but I think States have too much power in the national scenario and constitutionally should be limited. Let the States dictate local issues, not national ones. Trump said, "I'm the President" and that he has to right to overrule the Governors (which technically he cannot do constitutionally but should be able to do).
Rub a Dub