While Apple's decision to not include Flash in IOS devices arguably accelerated its demise, Flash is going to be obsoleted by HTML5 at some time in the future anyway. So I wouldn't put it this way.
Flash going away is beneficial for Adobe as well, as they'll have one less cross-platform virtual machine to maintain that they distribute for free anyway.
Adobe is in the business of making money from developer tools. Flash gave them an advantage as it was proprietary and had a large installed base, and there really was very little by the way of competition if you wanted a simple way to implement media in a webpage.
HTML5 and specifically canvas, video and to a lesser extent audio means that Flash is no longer the only solution.
However, is anybody else making tools for generating canvas animation and interaction tools? that is where Adobe makes it's money, so as long as they've got the best tool for the job, this won't be any financial change for them.
Flash going away is beneficial for Adobe as well, as they'll have one less cross-platform virtual machine to maintain that they distribute for free anyway.