Brake system or any other product based on engineering solutions, don’t run on opinion.I’ve been in the automotive fleet industry for 42 years. All of that time with first responder and law enforcement equipment. In my experience moisture and air enters the system via the master cylinder. If it could enter any other way there would be a breach/leak in the overall braking hydraulic system. The recreational brake flush madness for street driven passenger vehicles is designed for one thing - take your money. Leave the master cylinder top on and only remove when adding fluid. Our fleet was forced to run 200k due to budget reasons. No brake failures due to not flushing brake fluid, mysterious air, and mysterious moisture entry in the system. There was always a mechanical reason for any moisture and/or air entry. I’m old.. I wish you well with your brake fluid flushes. Rounded off bleeders ain’t my idea of fun. That’s my opinion.
One can get away with old brake fluid in certain geographical regions. Here in CO, it is bit more complicated, especially if one “rides” brakes on 6-9% grade for some 15 miles.
Also, for fluid to absorb moisture, you DO NOT need failed component. That is not how it works. Article above explains that.