The thick/thin paradigm is not entirely true. Although a thin head that has never been maintained/periodically thinned will perform better than a thicker head that also hasn't been maintained/kept very thin.
You've figured out that a thin axe bites deep with your experience. A thin axe also sticks-- both as a ramification of it's deep penetration, as well as fact that most very thin axes have no high centerline/point contact which allows the chopper to "wiggle" the axe out-- common in the old footage of good axemen. An axe that is "right good stuck" won't budge at all until it lets go completely, often requiring a mallet or a large branch to do so.
Your comment about the mauls is clearly hyperbole. An effective chopping axe has to balance penetration (thin) and wedge action/regulation of depth of cut (thick). A maul will not penetrate across wood grain. A very thin axe will not exert enough wedging force to be particularly useful for anything except sharpening bean poles and carving things. I own axes/mauls of both extremes.
Here's something to think about-- most all of the axes made during the era where significant amounts of wood were bucked using axes, either by homesteaders/farmers etc, or by the logging industry, were generally shaped like your example here. Almost all of the Maine made axes, supplied to the logging industry in the lumber capital of the world, were wedge patterns, 3/4 wedge patterns, Maine patterns, etc. These men were not splitting firewood with these axes, but rather notching trees, and if you go far enough back, bucking them to length (in the book "Tall Trees, Tough Men", there were accounts of operations using only axes up until 1900).
That's not to say that this axe, in it's current shape, wouldn't make a good splitter. Maine patterns, wedge patterns, etc make great splitter when they are worn out and not adequately thinned and shaped for chopping work. But that has to do more with the first inch of the edge/face than the overall geometry. If that zone behind the edge is rounded and dubbed off, you won't get much penetration, and plenty of wedging force. But if it's a "fresh one"/adequately thinned, they make excellent energy efficient cutting axes that really throw the chips.
Here's an example of a mostly untouched wedge pattern, that with a little thinning in that mentioned 1 inch back from the edge zone would make a perfectly good axe for cutting across grain.
