That is incredible. I never could get more than a handful of shaves out of a cartridge. Surprisingly my next shave with the Axe will be more than I've ever done with a cartridge.
I think cartridges, and all razors for that matter, dull to a certain point and then once that point is reached it takes exponentially longer for them to become more dull than they currently are.
So if you can make it to that point then every shave after that will feel the same.
My reasoning is because your beard isn't getting tougher after each shave. You are shaving the same thing over and over again so once the coatings and the initial super sharp edge is warn off, what's left? It's going to dull, and then reach that point of dullness where unless you are shaving a tougher beard or cutting something tougher/harder the edge will remain the same.
I understand why you would think this but it simply is not true. Every time an edge is exposed to matter it is cutting it loses microscopic material. There is no way am edge just gets to a point where it no longer dulls. If you were to shave with a de blade for a year straight every day, it could possibly lose a quarter inch of metal depending on beard type.
Not trying to argue, and not saying a blade doesn't PERFORM the same at a certain point, just saying it doesn't just stop dulling.