I mostly agree, except it's not "simple to customize" in even a majority of cases.
The 'upload and online', however, is and will continue to be the killer feature that will keep rails/python/java/etc-based CMS at a major disadvantage.
Starting projects today, I prefer Grails. Starting a project which I had an intention of distributing to a wide number of users (potentially for eventual world domination), I'd use PHP. Nothing else comes close to the ease of getting the widest number of people able to upload/install.
Yes, it might not be perfect, but it does well what it says it does, it's quite simple to customize and you just upload it online and you are set.
Being nice internally is good. Being working with tons of available plugins is better.