This is another "meme" that relies more on legal intuition than it does on legal and/or jurisprudential understanding of the constitutional application of inter-branch privileges and immunities and the precedential consequence of their explicit and/or inadvertent waiver. If this "sounds right" to you … you need to seek a better understanding concerning what you think you intuitively know. Understand, it is incumbent upon the branches of government to accommodate the legitimate privileges and immunities of their co-equal branches. Executive privilege is a legitimate privilege and immunity. Advisors to the President are legitimately and appropriately shielded from having to testify concerning their communications with the President.
When Congress issues a subpoena to a member of the Executive Branch, and there is an assertion of Executive Privilege, legal precedent requires that “each branch should take cognizance of an implicit constitutional mandate to seek optimal accommodation through a realistic evaluation of the needs of the conflicting branches in the particular fact situation.” This is known as the Accommodation Process. The Accommodation Process is “not simply an exchange of concessions or a test of political strength” but rather as “an obligation of each branch to make a principled effort to acknowledge, and if possible to meet, the legitimate needs of the other branch.” Where the branches are unable to resolve their dispute over the necessity for complying with the subpoena … or the propriety of the asserted privilege or immunity in that particular context … the party seeking the information is to file an action in the court of competent jurisdiction for an adjudication resolving the dispute.
Understand, none of that has been done by the House Democrats. You see, the subpoenas that they issued are void. The House Committee with proper subject matter jurisdiction is the House Judiciary Committee. The House Intelligence Committee issued the subpoenas. The Democrats have withdrawn the contested subpoenas and either dismissed the litigation seeking their enforcement or sought a determination of its mootness to avoid a finding that the wrong committee issued the subpoena and that both the subpoena and inquiry are void for lack of subject matter jurisdiction. The "impeachment emergency" was contrived to create a "we can't wait excuse" to give cover to their withdrawals and dismissals of the litigation seeking enforcement of the contested subpoenae that would have by now been resolved with an adjudication concerning either the necessity for compliance ... or the legitimacy or the asserted privilege or immunity. Wouldn't that have been better for the Democrat impeachment mob? Obviously not.
It's that simple.