I hate that it develops all the usualy, old XP flaws: getting slower and less stable over time, shutdowns that take forever, explorer going busylooping and hanging, ...
These things happen because of the applications you install. YOU are the cause.
Yes and no.
Obviously as you install applications that should run at startup, yes. If they integrate with the Explorer yes.
However, I work for a company, LANDesk, that has lots of applications that should start at "Startup" and we have taken many measures to make this not slow down startup as much (accept AV, we have to have that start ASAP).
Microsoft doesn't appear to do threading. If there are five applications to start, we should have an option to make them less priorty than the boot/login screen, because really, even though they start, the Login shouldn't be that much slower.
In Explorer.exe too. I have an issue that occurs whether or not any applications are installed or not. The main GUI in Explorer.exe still shuts down for weird reasons that are insignificant to what you are actually trying to do. For example, I have a huge problem with Explorer after waking up from hibernation that I have discussed indepth on my blog (I would link to it but I got in trouble for linking to my blog but just google for these words: Windows 7 New Folder Hang). I don't care what is happening in the background, if Microsoft spawned a new thread to do it and the gui continued on, this would not be a problem.
I don't care how well Windows 7 runs alone (with out apps) because nobody buys Windows 7 to run it only. We buy to run our apps. So the only thing that matters is how well it runs with our apps installed.
Installing applications does not have to cause slowness. There are many solutions to slowness caused by installed applications that Microsoft has failed to implement.
So Yes, it may be the apps fault. But Microsoft knows this and still failed to make significant changes to Explorer.exe and most of the rest of their OS to handle the problem that is "supposedly" caused by Apps.