There are some cautionary notes to be aware of when copying systems and parts of systems. This is especially true when you are using other people's outcomes as the target of what to copy. The first is that you may not be aware of everything that's going into their systems and all their systems are made of. Even if they describe and detail their own systems they may not consciously be aware of everything.
There also may be levels and bootstrapping, so while the current system they have works for them, there may have been earlier systems and set up to get to that point that needs to be achieved first.
Think of an example of someone making money in real estate as an analogy, you could copy exactly what that person does in setting up the right bank accounts doing the right research for finding the perfect property you can later resell. Only you don't have the money to actually purchase the property...
The real estate business system on its surface makes some assumptions about a starting point than in itself was produced by other systems, such as better money management and saving, career growth or money making in some other venture. This analogy also reflects that there may even be multiple paths to get to that point and some may not even be relevant to you (taking this analogy further maybe the person you are emulating had an inheritance from a rich uncle to kickstart their real estate business).