The web evolves at a rapid pace. Now that browser vendors are implementing new features at a faster rate, developers can deliver better experiences to end users with a greater degree of certainty that each will have the same experience the developer intended.
He isn't complaining about the fast release cycle at all, he just want its browser to do it without interrupting his workflow and disabling all of his plugins. You know, kind of like chrome.
So if this is just an issue of certain add-ons being disabled because they're incompatible with X version of Firefox (something that's always been the case), then we're merely in a transitional phase where the good developers with popular add-ons will have to adjust their development cycle to fit with this new trend.
@nolok got it right, plugin stability is incredibly important to users. It's also demoralising as a plugin developer if you have to spend most of your development time testing compatibility. Mozilla need to find a balance between a fast upgrade cycle and maintaing stability for plugins. At the moment I think things have moved to far from the glacial 2.x -> 3.0 to the flash flood like 4+ upgrades.
Maybe it just needs adjusting a little.
Look at how long it previously took Mozilla to get major releases (and major features) out the door: http://en.wikipedia.org/wiki/History_of_Firefox#Release_hist...
The web evolves at a rapid pace. Now that browser vendors are implementing new features at a faster rate, developers can deliver better experiences to end users with a greater degree of certainty that each will have the same experience the developer intended.