> IE was so bad because Microsoft tried to go off and create its own standardsThat's a common misconception, but what actually happened was that MS implemented draft CSS specs which ended up being a bit different from the final standard. At the time they were extremely eager to pack new stuff in IE (including a state-of-the-art XML/XSL processor!), so they rushed in a lot of stuff before other players had agreed how this stuff should really behave.
IE was then basically abandoned. MS just refused to fix their engine to adhere to newer standards. By the time this became to be seen as a problem, Netscape was dead, IE was dominant, and they were busy trying to plug the ActiveX security sieve, rebuilding on .Net and finding an alternative to Flash.
In this sense, Apple have done exactly the same with Safari: they poured resources into it while they were competing on the desktop. Now they only care about iDevices, where they have no competition at the browser level, the priority is battery time, and stability (aka rot) is preferable over innovation. Look at Safari for Windows: they built it only to support iTunes, and basically dropped it when iTunes on Windows became fundamentally unnecessary.
They went ahead when they wanted to be in the game, now they own the game so their incentives are different. Exactly what Microsoft did back in the days.