Not-that-small disclaimer: I use a black macbook as my main machine, and every time a webpage has some flash video/animation, the fans start to make a really loud noise and most of the times it breaks (some weeks ago it would crash Safari). As developer I’ve used Flash in the past, and it’s an experience far from enjoyable.
John Nack complains of the hate Flash is getting from the open standards people and tries to explain how it works. Despite the above disclaimer, I agree with him, and find Flash even more important.
Regarding the Mac OS problem, as Nack said only around 5% of the market share. Of course it’s not as important to Adobe as to work on Windows, but as this changes as more people buy Macs (check Apple’s numbers on this), Adobe will work on this issue and improve the quality of the plugin on Mac OS (don’t forget quite a few CS owners are Mac-centric designers, developers and artists). As for the iPhone/iPod/iPad, I believe that Apple is trying to prevent Adobe to prevail on the mobile, leaving space for Apple to expand.
Open Standards take time, everyone knows it. And Macromedia/Adobe was right about moving Flash forward in the proprietary road. As Nack said, the success of youtube and video online was only possible *at that time thanks to Flash. Of course now standards are catching up, and it’s possible to do video in HTML5, but Flash is in the exact same position as Gears.
The difference is that Google gave up on Gears but thankfully I don’t see Adobe doing anything similar anytime soon. They will continue to keep technology ahead of browsers (and open standards) making their plugin useful. Thinks like Webcam/Microphone/Streaming are not yet available in browsers, they need external plugin support (being Flash, Silverlight, Google Video Plugin or even some Active X thingy).
Technology will evolve (and browsers will become more important as we move to (More-)Web Oses) and plugins will bring them into the browser, then browsers will incorporate them as new technology raises and is embraced by plugins. This lifecycle will allow plugins to survive. Of course they will have to bet on the right features.