It is erroneous to judge the entire Rails community based on your experience with one person.
I used to have much of the same beliefs as you about Rails; Rails is not fit for highly specialized applications, a framework is overkill for very simple projects. It is only after I got further involved in understanding Rails that I understood that the framework is flexible enough to fit complex, simple and specialized apps alike. I challenge you to give me an example of a web application which is too advanced for RoR.
Sure:
Example one:
I have friends that works in one of the major social sites (not saying the name), and they tried ruby on rail, but failed to scale with it, both feature wise (modilarity), and sheer performance.
They tested side by side, and they had to add almost x2 the amount of servers for the same funcionality.
The mantra of Ror, is computers are cheap, developers/getting into marked is more important. When you are serving millions of users, that mantra quickly becomes expensive and hard to maintain.
They tried this in 2007, and still use ROR in limited capabilities (for some tools).
Example two:
Encoding video for potentially hundreds type of formats, for thousands of users at the same time. This is on demand video serving to customers where they have to scale in a two dimensional way (both users, and video formats). Even not trendy among many people in here, Java has one of the best and most advanced multi threading capabilities out there, especially with Java 6. So, they stuck with java for this part of functionality, and actually using Ror only for the wap front end.
Example 3:
Any custom search engine, api engine, anything that doesn't fit the CRUD mantra.
Sure you can modify Rails and get it to work for all the above examples, but it will be probably a poor fit for it. A different technology/framework, or just build your own web app without a full blown framework are better choices.
I hate it, when many people equate Web Apps with CRUD Apps, which I think it is a mistake.
We built a video transcoding platform in Rails - http://zencoder.tv and http://flixcloud.com. Of course, it would be stupid for us to try to actually do the encoding in Rails. That's what C is for. But Rails makes a nice lightweight queueing/management platform that can work alongside of other tools.
Each of your examples is a place where Rails isn't appropriate. But each example should be a multi-tier architecture, and Rails can happily cover one or more tier in each case.
I used to have much of the same beliefs as you about Rails; Rails is not fit for highly specialized applications, a framework is overkill for very simple projects. It is only after I got further involved in understanding Rails that I understood that the framework is flexible enough to fit complex, simple and specialized apps alike. I challenge you to give me an example of a web application which is too advanced for RoR.