Allah has showered His mercy over us by preserving for us the books of Hadith that the Ummah has accepted and transmitted for over a thousand years, such as Sahih al-Bukhari, Sahih Muslim, the Sunan, Muwatta Malik, and Musnad Ahmad. The preservation of Hadith is a job done by an Ummah of scholarship, not by one or two scholars of Hadith.
This is why you will not find a single Hadith (literally not one) in Sahih al-Bukhari, for example, except that you will also find it in other books of Hadith with sound chains of narrations.
Alhamdulillah the Sunnah continues to be preserved, and the few who have misunderstood or are not guided are also always going to be there, so that the people of Sunnah continue to be rewarded and raised in the sight of Allah for contributing towards spreading and preserving the Prophetic teachings, and removing doubts from it.
May Allah raise us with the imams of Hadith. Anyone who learns what they have gone through to ensure that the Prophetic guidance is kept pure will have great love and respect for them.