> Unless RDP and VNC have fixed their performance problems
They are both much, much faster than X11. X11 has higher latency and uses significantly more bandwidth.
> by putting the whole remote desktop in a separate window (instead of making windows for remote apps seamless)
Many of the things that make modern desktops nice (like client-side decorations) make it hard to merge remote and local windows. It's not impossible (witness VirtualBox's attempt), but there are peculiar corner cases if you want to make it generic across platforms.
If you want a modern desktop that's fast on modern hardware (arguably its primary purpose), remote desktop will have to work RDP/VNC style.
I do 99% of my development in the office in an eclipse instance running on a remote server connected via LAN. It's completely seamless, you would have absolutely no way of knowing that it's not running locally. Having never use RDP, I can't rule out it's as good; I don't see how it could be better. VNC is laughably bad in comparison.
For working from home, we've got NX. Again, it mostly just works; I can't really tell that it's a non-local window. Again, I can't rule out though cannot imagine RDP does it better; some amount of latency is unavoidable via WAN; VNC would be excruciating.
This setup has been working fine for about 6 years now, btw.
I am also using NX (specifically, Nomachine's NX, an older version before they replaced everything with proprietary crap.) Right now for Linux, I think it is still the best thing going. I use it in full desktop mode, as if it were a VNC or RDP session. Offsite, there's very little latency or artifacting. Onsite, as you say, it's nearly indistinguishable.
They are both much, much faster than X11. X11 has higher latency and uses significantly more bandwidth.
In my experience, this hasn't been the case. Running Emacs via X full screened across two monitors (both at 1920x1080) is much snappier than running VNC from a Windows box, single screened, lower resolution (can't remember exact numbers just now) and lower BPP. Of course, that could just be the typical disparity in IO performance between Windows and Linux.
And while I grant that X sessions can't be detached by default, there are solutions for that (see XPra further up thread). There's also been compression for X quite some time. On top of all of this, you don't even have to be running an actual GUI on the serving end; can the same be said for RDP and VNC? Or Wayland?
If your concept of "network transparency" is "remote desktop", then you're undoubtedly right. But that's not the only use case for X11 (or even the one it was developed for). Many of us are just fine pushing an individual app back to our display without having to load up VNC.
They are both much, much faster than X11. X11 has higher latency and uses significantly more bandwidth.
> by putting the whole remote desktop in a separate window (instead of making windows for remote apps seamless)
Many of the things that make modern desktops nice (like client-side decorations) make it hard to merge remote and local windows. It's not impossible (witness VirtualBox's attempt), but there are peculiar corner cases if you want to make it generic across platforms.
If you want a modern desktop that's fast on modern hardware (arguably its primary purpose), remote desktop will have to work RDP/VNC style.