A short hollowgrind similar to a pocket knife fails miserably in a big chopper. Not only is it fragile due to a lack of support.
I agree that a fat convex grind is the way to go for a splitting axe. Or a knife that wants to be a splitting axe.
The misconception is that a hollowground knife's edge is "fragile due to lack of support."
If you take a CARBON steel kitchen knife (some stainless knives - cheap or high end, doesn't matter - are too brittle) and you hack on a tree with it, the edge will roll and/or chip. But the damage is limited to a small fraction of an inch past the edge. A hollowgrind doesn't need to go that thin. On top of that, the damage is all starting at the cutting edge, due to the acute edge angle on the kitchen knife. Just by slightly changing the final edge geometry by setting in a more obtuse microbevel to the appropriate depth, that carbon steel kitchen knife can hack away all day without failing. As could a hollowground knife with the appropriate grind and edge.
This begs the question, why are so many pocket knives so thick to where they even need a hollowgrind at all? Why is the blade on a Mora knife only 0.080" thick, and the blade on a Kershaw Blur abour 0.125" thick? Partly, it might be because that specific Kershaw uses a more brittle steel. But mostly, it's market demand. That's the kind of knife that people want to buy. They like the weight, look, or whatever. And it makes a better prybar.
If you have steel at least say, maybe, 30-45 mics (depending on the steel) thick behind that final edge bevel, and a crack goes back far enough to reach the hollowground area, the entire blade was going to snap in two, anyway, regardless of the primary grind.
Now consider that no matter how fat you make your primary grind, you still have to put an edge on it. That edge angle is what determines whether the edge on your 2 lb, 1/4" thick chopper is going to fail or not. The type of alloy and heat treat, plus that edge angle are primary determining factors on whether the blade is going to snap while chopping. The thickness of the spine affects lateral strength, primarily. And the thickness of the primary grind approaching the edge does affect cutting ability (sticking vs splitting) where chopping wood is concerned, I agree. But it does not add significant strength to the edge.