This, and about the same ratio.I wait politely for a few moments, and if they don't step out of the way, I ask politely, "Excuse me." 99.99% of the time this leads to them moving their cart/kids/scooter out of the way and an apology on their part.
Does this not work for you?
The only time I recall getting a negative response was at a small grocery store, where an older lady was diligently inspecting cuts of meat. Her cart was in front of the area I was interested in (and not where she was looking).
After waiting a bit, I said something like "Excuse me Ma'am, can you please move your cart?"
You'd think I insulted her, her heritage, her kids, and any future generations. She never said a word, just grabbed the cart and completely left the area in a huff.
But IME, folks are mostly nice if you're polite.