It seems there was a huge loss of software in the 32bit->64bit switch. Code bases in Cocoa were too heavy to switch to Swift (or whatever the specific languages were). FCPX is such a different version than FCP. Just like QTPlayerX is so different than QT Player 7 Pro was such a regression of capabilities. I doubt there was a "this is the best QT Player we've ever released" on that "upgrade".