The line seems like a gross oversimplification because by its very nature, just about every successful revolution where an existing government is overthrown, the power of the previous government had decayed to the point where the revolutionaries' power overcame the existing government. Where that 'intersection point' is differs by each revolution.

However, to be fair, the statement does capture the essence of what occurred. By 1911, the Qing Dynasty had decayed from foreign intervention, unfair treaties, and a child had been enthroned in the line of succession.

The revolution succeeded, but China was basically splintered into the warlord era. Sure, the Republic was declared, but their power was concentrated in a small area while warlords and other parties with an interest in maintaining or gaining power ruled the other parts of the country. So in that essence, yes, one could say that the Manchu's had decayed to the point that when they abdicated, the Nationalist revolutionaries were less responsible (as they did not have major influence much less control over the vast majority of the country) than the Manchu's simply falling apart. It would of course take years to establish a national army and then years more of civil war (or forginging alliances) against the warlords and other groups to establish control, and even then full control never really quite happened