I don't see where I said Firefox's existing fragmentation was bad. I responded to the claim that "Almost all users of Firefox and Chrome are using the most up-to-date versions of those browsers". The stats you posted show that this is not the case for Firefox. I don't think 87% can pass for "almost all users".
Firefox 3.6 has been out over one year and, according to those stats, there are still ~13% of users who are using earlier versions. If Firefox 4-7 are released in 2011, without automatic updates, it would stand to reason that fragmentation could increase.
Firefox 3.6 has been out over one year and, according to those stats, there are still ~13% of users who are using earlier versions. If Firefox 4-7 are released in 2011, without automatic updates, it would stand to reason that fragmentation could increase.