Enterprise and mysql?

Question

MySQL

Why don't most big IT companies use mysql? Almost everywhere it is mssql or oracle, occasionally nosql solutions.

Answer 1

The main reason is paid support. Suppose if a mysql bug pops up unexpectedly, then no one will fix it for you here and now, but microsoft or oracle will fix it.
On these databases, they usually do what is related to money, everything else, even corporations do on postgres or mysql or mongo.