This machine is in no way being marketed as a 20 year machine. I would put it right there with Lowes/Home Depot models. 2-5, maybe 7-10 years, depending on how its maintained. Keep in mind, there are areas that are not allowing gas mowers to be sold in the near future, so we need to remain optimistic about this. Otherwise, we'll get left in dinosaur land, and it will only hinder our ability to work on and sell these machines in these areas, while other manufacturers take over. There is still service money to be made here, but it requires an open mindset.
I have many of the same questions/concerns as you all, but I am also an optimist. No way will this machine make our gas mowers obsolete, so I don't see them as a threat. Kinda like gas vehicles will never go away. The industry has a long ways to go in regards to battery safety/longevity. I also wouldn't put it past insurance companies to charge a higher rate for home insurance if the owner has all battery operated machinery. I would consider that much higher risk!
All that being said, I have no intentions of selling my old 1964 110 that my great grandfather bought brand new. It's my main mowing machine and will last my lifetime. I do have a GT225 and a Z950M that helps take some work load off the 110, but I use the 110 mostly because it just fits my style better. My yard is only 3/4 acre, but I like my mowing toys! I use the Z950M when I need to get the yard done in a blast. The GT225 is just for fun. It was in too good of shape to pass up.
I'm only 42, but I was raised with an older generation mindset. However, I've also learned to embrace new tech with curiosity and optimism.
We shall see what happens once we actually get our hands on one of these new machines.
Right now, it's online pre-order only.