I think your perception/use as per point 1 is the direct cause of point 4.

While the N900's resistive screen certainly takes some force beyond just 'touch' (which I personally always liked, I want to be able to make contact with the screen surface without the screen thinking I want it to do something, but I can understand why it can get annoying for others), I would never describe it as requiring any substantial strength or force or whatever.

When using the N900, I never even notice that I'm actually pushing into the screen at all, unless I consciously think about it (such as when people used to capacitive screens are trying to use N900s' touch screens).

I've had three N900s since summer 2010, which puts me at about 3 N900s / 4 years. An annoyingly short lifespan. The problems that ultimately made me get new ones were the telephony disabled errors, but I continue to use them in secondary capacities and in my usecases, I've never worn out a screen the way you describe. *Shrug*