Of course they are afraid of cannibalizing their other overpriced stuff. So they wanted to let it die a slow and painful death.
In he grand scheme of things getting rid of the pesky competitor MySQL was only an afterthought in the decision to buy Sun, that was probably driven by the legal department.
Also Oracle is pretty strong in the corporate Java space and has some great products there.
So MySQL did never get the attention it deserved and needed to thrive.
And by great do you mean "fucking awful albeit reliable"? That's always how I saw Oracle products. A pain at every turn, but it works.
Last I heard, that's why Oracle developers earn more than most: No one wants to do it.
Not long after this, Oracle acquired Sun and along with it, MySQL. One of the MySQL founders didn't like this and started a fork of MySQL, based on the GPL'ed source. There's not a great deal Oracle could have done about this. But they weren't just buying MySQL, they were buying all of Sun. Additionally, the fork wasn't exactly a commercial threat for years - it's only now that we're starting to see movement towards adoption of MariaDB by high-profile, large users.
Based on his constant whining BEFORE the Oracle purchase, that guy would have ended up starting a fork anyhow.
FWIW the only way MySQL was usable for real work was InnoDB, which was an Oracle product too.
same thing ;p