And this is true. But I do think most teams (if not all) that use Scrum give themselves a big advantage. They are more likely to be more successful if they use Scrum. And if they will fail, that failure is more likely to be identified sooner. Which is actually a win!
OK, so what are the 3 drivers of productivity in Scrum?
Well, I want to focus on some not-so-obvious things. Not the explicit dance steps of Scrum, but other things.
1. Creativity. The team can and should be more creative than before. Well, we all can always be more creative. And one thinks that the Scrum team enables more creativity. In every meaningful dimension relevant to their specific situation.
2. Velocity. By removing impediments, the team can increase their velocity, as measured by story points completed per Sprint.
3. "The vital few." By selecting the very least amount of work (features) to do (that still make up a minimum marketable feature set), we can get it done more quickly, not bore them with features they care little about, and make the system more elegant and easier to maintain and grow. This can lead to much much greater productivity.
It may be easier to talk of these three things as completely separate. But, just as it is amusing to speak of body and soul as separate entities, it is more fun to live them as joint and inseparable entities.