But that simply isn't true. The 22nd amendment wasn't ratified until 1951. Roosevelt didn't decide not to run in 1908 until well past the half-way point of his second term. He wouldn't have know he wasn't up for re-election. In fact, he came back after 4 years to try and take the White House again in 1912.
And gave us racist Woodrow Wilson.
Theodore Roosevelt's cousin Franklin was the one who finally put it to bed, requiring a constitutional amendment.
But even without the amendment it is true. Here is a political cartoon from the time period illustrating.
Prior to progressivism, we had people and politicians moral enough to willingly step down in addition to rejecting such things, simply because it was the right thing to do. Now they all want to be tyrants. That's what 100+ years of progressivism will result in.
Teddy was a dreadful president.
His reputation is saved by his very worthy military record and the fact that scumbag Wilson came so soon afterwards.