Is PS dead? I think that is a very extreme point of view. I do not think it is dead or will die in the near future. I remember when GIMP was taking over because of being opensourced and much more easier to use many were saying PS was dead, but it wont die so easily.
You already mentioned the reason, they have a very good stronghold in the market and a popular reputation. I have heard of capture one but I need to look into the others. Maybe then I will change my mind