Yes, "a good oscillator (clock) is a good start". Without a good start, you have nowhere good to go. So what is this argument about?
The issue is implying that only a good oscillator is required. That's what the argument is about. It purveys the wrong impression.
This is like saying that only a good D/A chip is required and you have the perfect DAC. Not by a long shot.
Like most things, the devil is in the details.
Steve N.
Empirical Audio