Is it actually a problem of fragmentation, or is it that some projects after a few years (and some amounts of donated money) just go into technology decline?
Apple wanted a web browser without depending on Microsoft, so they had to decide between reaching an agreement with Opera, or embrace Mozilla, or use the KHTML engine from KDE. They chose the latter, and forked it because they had to change too much (I guess). Then Google, even though is the main supporter of Mozilla, decides to create yet another browser, but not based on Gecko. Instead they pick up WebKit, but ditch JavaScriptCore and replace it with V8.
Now the even funnier thing: years after Android and Chrome are released, the default browser in Android is not Chrome. WTF? Even more amusing is the fact that WebKit is probably the only thing that is not heavily customized (like Linux) or written specifically for Android (like the rest of the userspace).
Are companies like Google or Apple in a technological decline? Hell, no. Is just that software is freaking complex, and to do it right you just need to focus on some things, and reach compromises. That leaves some people behind, and creates niches for different products. As simple as that. This "fragmentation" or "duplication" is simply a consequence of the freedom of people and companies to do whatever they see fit. And it doesn't matter if it's a FOSS project or a big evil corporation. It happens from time to time, and yes, sometimes it could be improved, but it isn't such a big thing IMHO.