"Taking down" a President and his cronies is not as simple as most people think. In fact, it's very difficult, indeed. Nixon resigned. Clinton didn't get removed after being impeached. No President has ever been impeached and removed from office.
Short of the impeachment and removal process, there is no real way to remove a President. Yes, some of those surrounding him can be removed or imprisoned, but the President has a position that is very well protected from such actions.
People mention Article 25, but generally, they have not actually read how that process works. It's not a viable way to remove a President permanently and is even more difficult than impeachment and removal, since it requires 2/3 majorities of both houses of Congress.
So, Mueller is not going to act soon. Really, the investigation is still in its early stages and is still organizing itself. I'm sure it will be done thoroughly and expedited as much as possible, but nothing is going to happen quickly. It really can't.
Really, the only ways Trump will leave office soon will be through resignation or if he dies unexpectedly. It's highly unlikely that he will be forced out of office, given the Republican majorities in both houses of Congress. The best outcome of the Mueller investigation would be enough damning information to force Trump to resign.
That's how it is, I'm afraid. When a President takes office, it's very difficult to get that person out of office. Nearly impossible, in fact, short of a resignation.