I actually HAVE seen a broken Estwing Axe!
Back in my Boy Scout days, the troop had a long handled campers axe that was nicknamed "Baby Blue". It was perfect size for the younger, smaller scouts to manage and was probably very much abused over it's lifetime- I'll bet the thing was 20 years old when I joined the troop... It was the designated axe all the 11 year old boys used when earning their Totin-Chip and every scout learned how to sharpen an axe by practicing on "Baby Blue". As a consequence, I'm sure you can imagine that the edge was usually in a less than ideal state. I'm sure the handle suffered quite a bit of impact damage from Scouts hitting logs with the handle rather than the head as well. On the rare occasions when the adults weren't around (at the showers, in the "Kybo", etc.) "Baby Blue" was occasionally pressed into service as a "throwing axe" (which really did SEEM like a good idea 20 years ago...).
My last memory of "baby blue" was seeing it laying on the floor of the troops gear trailer in 2 pieces, the handle snapped off 2-3" below the head. I'm not really sure who broke it or what they were doing when it happened, but the thing snapped CLEAN off... The Troop replaced "Baby Blue" with another Estwing long handled campers axe. I really don't know how long the new one lasted, but given the abuse I witnessed the first one take, and the abuse I assume it survived before I got there, I'd say the durability of the product is pretty impressive!