MySQL still isn't on par or better than its most comparable peer, Postgres. It's still nowhere near as terrible as Mongo, but let's not pretend it's amazing when it's merely serviceable.
Postgres got proper non-hackable replication in version 9... And it still isn't that great.
"Isn't that great" how? In that it imposes a bunch of limitations on you? Or that it frequently breaks and slaves have to be manually syned? Oh wait no, I was thinking of mysql.
MySQL replication is the one place it's got the edge.
Is it not the case that back in the day MySQL was better suited to running small to medium website backends with simple schemas out of the box? I know this hasn't been the case for a long time but I think it might be a contributing factor to MySQL's success.
The advantages were ease of installation on Windows, and network effects.