It's an interesting question then; the situations I see are the opposite: MySQL is the compatible solution already functioning, and a user would have to choose to change to Postgres.
Change what? You still seem to be unable to comprehend what he said. He was saying that if he was writing a new app that required a SQL database that he can't see any reason to choose MySQL over Postgres. Where are you seeing anything about changing databases? And secondly how is Postgres not a compatible solution that already functions? In what way is it either incompatible or nonfunctional?
Hey ("barely able to read"), thanks for being childish. It adds humour.
Well considering how you seem to be unable to comprehend basic English sentences one has to question your ability (or inability as it seems) to read.