You just answered your own question.
Seriously though, the Northwood generation might have been good (though Intel arguably got lucky in that AMD's initial 130nm process turned out to be a dud, stranding the Athlon XP at low clockspeeds for the better part of a year), but Willamette was underwhelming, Prescott was absolute garbage, and probably the only reason they even bothered releasing Cedar Mill was to fine-tune their 65nm process ahead of Core 2's release. 1 good design out of 4 isn't exactly the best batting ratio.
yes, but saying P4, in general, is bad is stupid. Willamette at 1.5ghz was a decent upgrade to the P3-1000. The reason it was an awful chip is that you were forced to
buy RDRAM which was insanely expensive and at the time we were just a few years removed from massive SD ram prices. Northwood was great but, what people
forget is what made it great was the DDR chipset and then the 800mhz FSB with dual channel DDR.
I remember being 14 and Intel launching their granite bay dual channel DDR chipset, I worked at a pizzashop at night and worked my ass off to buy the asus P4G8X,
DDR400 DC kit, and a S478 celeron 2ghz. It would be another 2 months before I could afford the P4 3.06HT. That celeron managed to overclock to near 3ghz and was one of the best Intel bang for the bucks ever.