The number of illegal activities were so large that one was bound to come out and lead to the uncovering of the others. Nixon was too willing to use the power of government to settle scores and get even with enemies.
The failure of the system to deal quickly was attributable to Nixon`s lying, stonewalling and refusal to come clean. So it took 26 months for the final truth to be known.
The fact of the Watergate cover-up is not nearly as interesting as the step into making the cover-up. And when you understand the step, you understand that Richard Nixon lied. That he was a criminal.