Sun couldn’t handle the cold. Obviously in terms of the dotcom bubble burst, inobviously in terms of the company’s character. The things people loved about Sun (giving Java and NFS away, treating engineers as the point of the company, McNealy's loyalty to his people) were exactly the things that kept it from doing what it needed to survive. Very warm, very caring.
Oracle expressed the opposite. Within a year or two Larry killed OpenSolaris, let the MySQL, Hudson and OpenOffice communities fork away, sued Google over Java, and watched Gosling and most of the engineers who embodied Sun walk out.
The part that rankles the most, and undermines many a retrospective I think, is that Larry the lawnmower turned out to be a better steward of Java & MySQL than Sun was. Coldbloodedness is a survival trait.
I am not sure if Java would have survived Oracle without OpenJDK being started well before the acquisition, or without IBM.
Since then, companies had to develop policies about installing JVM from anywhere but official java.com address, ban VirtualBox, and so on, because the lawnmower is lawnmowing.
And I do not really think Sun/Java is in anyway major income source for Oracle other than the form of providing integrated database appliances cheaper than previous deal with HP-UX on IA-64