How about Saddle Soap? Have you tested any? How basic is it? pH 7.1 and pH 14 are both basic and are quite different in terms of strength.
Blood, salt water, hard water, bleach are all basic, but they are quite different...
The short time that saddle soap sits on leather surface before rinsed off is not going to alter the pH of your leather shoes to any significant measure. It took tanneries hours if not days to alter the pH of leather using highly alkaline solutions and highly acidic solutions. How could anyone seriously believe that a couple minutes of contact with saddle soap is going to have any measurable effect on leather pH?
I did. Didn't get the chance to do it yet.
You are welcomed to try as well if you are curious enough and have saddle soap on hand. I only have the Saphir one.