You are essentially correct in terms of pricing, but you are missing one small, but crucial point: portability. If you essentially read at home, then carry on as normal. But if you travel a lot, have a long commute, or study and have to carry (heavy) textbooks from one location to another, then an eReader comes into it's own.
I'm currently (studying) in China, and as well as weeping as a semi-early adopter (Booken Opus owner - sitting on my desk back in the UK), I'm really missing being able to read without buying / shipping books that will either have to be donated or shipped back to the UK. I'm already loaded down with Chinese text and grammar books that will need to be shipped back!
The UK Kindle is now priced at a level where I feel people will be prepared pay, including a number of features that one would expect as standard (but sadly haven't been from some previous eReaders) e.g. decent bookmarking, annotations - plus being able to download books without having to connect to a Pc and use software to download one's book to a Pc, then transfer it to your device.
Storing your library in the cloud, then being able to access one's library from any device is the cherry on the cake.
I'll be purchasing an UK Kindle upon my return - simply because my Booken Opus fails in some crucial areas in terms of lacking a decent bookmark function, no annotation function, having to connect the device to a Pc, install yet more 3rd party software to simply transfer books to my device (small but aggravating point - also why I'm seriously thinking of buying the HTC Desire, so I can finally rid myself of iTunes), and I really dislike the page-turning transition on the Booken Opus. Whilst I was initially impressed at the accelerator function to be able to turn the device and read books in wide-screen, Apple slick it ain't! The stutter and flicker as it turns - although small - begins to irritate with time.
Standard advice before you take the plunge to buy an eReader: check to make sure that the books that you wish to read are available - particularly if you wish to buy textbooks for study purposes, or wish to buy certain books that are only available in certain regions (it's like regional coding for DVDs all over again!).
One question vis-a-vis regional coding: does anyone know if one purchases an UK Kindle, will one be kicked square in the balls by regional coding i.e. books only available if you are located within a given region e.g. US, Europe, yada yada yada? The reason for asking it would be a pain whilst travelling (or living / studying abroad) to want to be able to read a book, then find you're prevented from purchasing due to regional coding!