If Monty wants it back I'm sure the 1Billion he got paid can be used to pay to redevelop the code.
Oracle has no incentive to kill the MySQL ecosystem, it's going to be their low end competitor against MS and SAP products. It has more value to them as a working system than a dead one. If that had been their intention to kill MySQL they could have done immense damage when they acquired INNODB, at least temporarily. Yet they continued to develop and improve INNODB just like they will with MySQL.
Oracle's bread and butter is support contracts, not license revenue. MySQL buys them another market to sell support into. Just speculating but they also will have the ability to make it possible for MySQL to use Oracle for it's engine, bringing some heavy advantages to high availability LAMP stacks where customers are already using Oracle on the backend and replicating into mysql for the LAMP application. Monty's big fear is he's built a company (MariaDB AB) doing the same thing with the MySQL code as he had with MySQL AB and he's worried that Oracle will shut him out or kill the ability of commercial forks and force everything GPL. As they have used the GPL as a marketing threat (they told all their customers using the GPL branch would force them to GPL their databases) and now he's scared he will have to operate in the GPL ecosystem knowing he has nothing to offer by reselling the same code anyone else can.
Monty is a liar, Groklaw caught him in the lie and he shouldn't be trusted. Let him use all that money he got paid to redevelop a closed source DB if he wants to have a proprietary product. He's abusing the EU approval process for personal gain.