I've seen some screwed up Rails and Django projects, but the severity of the damage is never, ever, as bad as a bespoke PHP application. It's not even in the same league.

Remember, both PHP and JavaScript were serious tar-pits ten years ago.

JavaScript has made enormous strides in that time, the cultural shift is unbelievable. People went from writing absolutely terrible client-side code, to using frameworks (Moo, Scriptaculous at first, later jQuery, RequireJS) to using it server-side for serious applications. It's gone from complete anarchy to highly civilized. There's some things JavaScript does very well now, and in an elegant way mostly free of quirky tradition and/or obnoxious anachronisms.

Meanwhile PHP has only degraded. It's improved, technically, but the community is now hyper-fragmented. Best practices are routinely ignored. Frameworks don't inter-operate even on the most basic level. There's no leadership. There's opposition to even the most obvious improvements to PHP, like deprecating components that are doing nothing but holding PHP back. Killing off `mysql_query`, for example, is absolutely imperative, but it's going to be a bitter fight.