One might be puzzled by my response, but I say no because technically anything can be fixed, the only question is how.
I've been struggling with this issue lately myself as my own laptop (which is not underpowered by any means) has been experiencing incredibly slow login times for the Windows 7 install I have on my HDD. I also have an install on my SDD, but aside from bootup the performance difference is negligible for me(I also use it a lot less so it doesn't have all my software installed). The hard drive in this case is a 2TB Samsung Spinpoint M9T at 5400 RPM. Slower RPM, but it's a super dense 2.5" laptop drive.
I've made some progress in speeding it up, especially the login time which was atrocious... Removed an update that caused some Windows crap to be re-verified or something all the time, removed several things from startup and switched non-essential services to automatic. Eventually I did get the logon process to not be too bad and Windows would become responsive after maybe 40 seconds instead of 5-10 minutes. It's still not as fast as I'd like, but it's much improved.
But the problem with this is that I'm shooting in the dark and have to rely on trying pretty much every suggestion on the web there is. And here is the difference between my Windows installs and my Linux installs. GNU/Linux is open source, virtually everything you use in it is. The system is also designed to be tinkered with and the bootup processes are all opened up for any level of configuration that you desire. You can screw with your init system, the kernel itself, your bootloader, anything... So with the sources to all these pieces, I think figuring out what's wrong is relatively easy.
Come Windows, everything is closed source. The problem can be fixed, but you're stuck with decompiling and trying to debug perhaps even the kernel itself if you want to solve any problems. How are you going to profile bootup or login times? Can you easily find a sink for disk or CPU usage in certain functions in the Windows source code? Probably not. It's really challenging to figure out what's going wrong in this case. The best I can hope for is to look to people who have gotten a lucky guess or someone who is so absolutely hardcore that they've debugged a closed source operating system.
Just my 2 cents.