OK, so why hasn’t there been?
Because it is the Mutual Assured Destruction of politics.
One party impeaches and removes a President. The next time that party holds the White House...that President WILL be impeached and removed.
The closest we have come in modern times is Richard Nixon...and I doubt he would have been removed.
The Impeachment card is a Fund raising tool. For Both parties.
The only way it will happen is if one party controls Both Houses, by a Large majority, the other the White House, and 75-80% of voters say the President Has To Go. By the time that happens a President will pull a Richard Nixon and resign.