Because costs are extremely low for AT89S52 for instance, here in Germany!!
well, you get what you pay for
And please remember that Philips' chips also shows buggs from time to time...
Oh yes, but, at least they are very fast with admitting it, as opposed to Atmel, you usually see a problem in the errata before you discover it yourself.

Atmel was very successful with AT89C51, when they combined their proven flash memory technology with '51 core. The flash was good, the controller needed to go to rev s or beyond.

Nevertheless their support is lousy and offending
I'll let that one stand by itself
Is this a cause of globalization?
I do not think so, here in the US many manufactureres cut their support staff to the bare bones and ask the distributors to provide the support. So info is now usually one step away from the horses mouth.

Erik