Because S. Jobs got rich via multiple market-changing products. It's as proof-is-in-the-pudding as you can get. There are not many practical alternatives. Careful scientific studies would be nice, but nobody is paying for them so far.
Re: "technique called Appeal to Authority"
More like "appeal to merit".
That being said, good factoring takes work. You need both raw logic and math-like ability to identify patterns and propose reworks, and also you need to understand the domain so you know what can be chopped, reworked, and/or consolidated without harming operations. Often when talking to the subject matter experts, I say something like, "I see a pattern here, but before we rely on it in the new system, how likely is it to change in the future, and what kind of changes are likely?"
Re: "technique called Appeal to Authority"
More like "appeal to merit".
That being said, good factoring takes work. You need both raw logic and math-like ability to identify patterns and propose reworks, and also you need to understand the domain so you know what can be chopped, reworked, and/or consolidated without harming operations. Often when talking to the subject matter experts, I say something like, "I see a pattern here, but before we rely on it in the new system, how likely is it to change in the future, and what kind of changes are likely?"