I am trying to explain that if companies are afraid of vendor lock-in, they can migrate from Solaris Oracle database to Linux Oracle database. The same on IBM DB2 database. You can migrate from AIX DB2 to Linux DB2. It is quite easy to do, if you stay with the same database. Thus, there is no reason to be afraid of OS vendor lock-in. There is a Database vendor lock-in.
But in this discussion, that is not relevant. Because we are discussing OSes, not databases. And you can freely switch between OSes, as long as you stay with the same database.