4 days shouldn't. A minority of Android devices, notably the most recent flagships, are getting decent upgrades.
But even a glance at what version of Android is being used: http://developer.android.com/about/dashboards/index.html shows that over 2/3 of all Android Users are still on 2.x or before, and it's very likely that many of them will never have an opportunity to upgrade.
That gets me frothy. iPhones get 3 to 3.5 years of updates, and Android devices averaged on whole are getting what, 1.5 to 2 years? Maybe less, considering how many aren't being updated?
The answer of "only buy a flagship" is bunk. If Google supported that answer, they should cut out the cruft. But Android is more than flagships.