In 3 words:
They already do.
MySQL Enterprise is more than just a binary. http://mysql.com/products/enterprise/ has the details on the other features MySQL Enterprise includes.
One of these features is the MySQL Enterprise Monitor, which is closed source, proprietary alerting software.
So when bloggers make statements such as:
MySQL will start offering some features (specifically ones related to online backups) only in MySQL Enterprise. This represents a substantive change to their development model — previously they have been developing features in both MySQL Community and MySQL Enterprise. However, with a shift to offering some features only in MySQL Enterprise, this means a shift to development of those features occurring (and thus code being tested) only in MySQL Enterprise.
All they are doing is showing their lack of knowledge about what MySQL Enterprise really is. Complaining that MySQL will likely charge for online backups is a valid one, but currently InnoDB Hot Backup is for sale only. There are solutions out there that do not cost anything, but nothing that MySQL produces. The only free [mostly] online backup product is
mysqlhotcopy, and that has limitations such as “for MyISAM tables only”.
While I have said that software should be open source and free, where “free” means “free as in water”, that does not mean that we should take it for granted that free software will always be there. The path to that is to have a contrast of software one pays for, and software one does not.
Of course, that is not why MySQL charges for the software. They charge for some of their products because without money, they cease to exist, and then even the free version stops being developed on.
“A necessary evil” is a dangerous phrase, and can lead to a slippery slope….but in this case, I do not envision that it is a big problem. Maybe I will regret saying this if things keep getting more and more closed, but I do not believe so.
And I, too, am frustrated that we have been told that “online backups are coming” only to find out that they may not come in the means I expected. However, software is not bug-free, often does not come out on time (MySQL 5.1 itself is a year late!), and sometimes, promises get broken.
My faith in MySQL is unbroken, and I hope most others reading this feel this way as well.