That's a common problem with a lot of web frameworks. Every single one of them claims to make "web development" easier. They promote themselves by showing how well they solve some narrowly-defined and often imaginary problem (in this case - client-side updates), but completely side-step all the typical issues that really make web development difficult: user and group management, caching, validation, authentication, permission handling, stuff that prevents XSS, CSRF and injection attacks, version upgrades, dependency management and so on.
Anything can be made to look easy if you're ignoring real-life issues. Heck, you can do seamless client updates by refreshing all the pages on my website every second. It will be inefficient, but it is easily doable.
I think you take for granted some features commonly provided by modern web frameworks addressing what used to make web development difficult. For example, in the pre-Rails era, building just a simple CRUD website used to be difficult.
For arguments sake, if we say there are 20 "real-life issues" then all web frameworks tend to address up to 12. New frameworks are created to address some of the issues of the past frameworks but with regressions in other areas.
Recently, I've been using Lift which happens to be very strong on most of the points you named, yet in retrospect, I don't feel it made web development easier overall because it has other deficiencies.
Anything can be made to look easy if you're ignoring real-life issues. Heck, you can do seamless client updates by refreshing all the pages on my website every second. It will be inefficient, but it is easily doable.