Republicans have had ample opportunity to impeach and/or indict either of them. They can't, and they won't, because they know charges wouldn't stick.
They can vent and fume all day about alleged misconduct, but it's just hot air. Obama ran one of the cleanest Administrations ever.
Trump's? Not so much. The Mueller probe generated a lot of real indictments and convictions including many close to Trump, and while it didn't produce enough tangible evidence to implicate Trump directly, it hinted at a lot of what we saw him do in Ukraine.