Are we headed towards or away from computer platform stability? In the very early days of computers, each one needed a custom operating system, because they were all that different. As time went by, hardware started standardising, and so did operating systems, through the mainframe days into desktops and servers. For a while, there was peace, with just a few desktop operating systems, and that is still the case to an extent, but there are more minor OSes popping up every day, usually based on Linux, because it's open-source, and even the new versions of the major platforms fail to completely displace their old versions (Windows XP is still going strong, despite being unsupported and now superseded three times over).
So is it going to get better any time soon? Probably not. Until it is legally mandatory for every mobile phone to be equipped with a factory reset button that installs stock-standard Android without carrier and manufacturer cruftware, all those custom tweaks will make life hell for developers like me, unless we resign ourselves to a lifetime of complex server-side development with tools that were meant to make images change on 1990s websites.
Mokalus of Borg
PS - Right now, to target "every major platform", you need at least six versions of your app.
PPS - Which is why so many people just make a website and call it an app.