Why do people say the PS2 started out slow?

[DKII]

NA sales, first 5 months for PS2, PS3, GC, and Wii (March '07 estimated):

 

PS2		PS3		GC		Wii
Oct-00	453,500	Nov-06	220,500	Nov-01	728,750	Nov-06	538,500
Nov-00	214,000	Dec-06	533,250	Dec-01	571,500	Dec-06	704,750
Dec-00	642,250	Jan-07	273,000	Jan-02	62,000	Jan-07	485,000
Jan-01	274,250	Feb-07	133,750	Feb-02	85,250	Feb-07	379,250
Feb-01	262,000	Mar-07	200,000	Mar-02	114,750	Mar-07	450,000
Total	1,846,000	Total	1,360,500	Total	1,562,250	Total	2,557,500

 PS2 and Wii both severely supply constrained for the entire period.  PS3 in plentiful supply and is the worst of the 4.  The "slow starter" PS2 outsold the supposed "fast starter" GC in the first 5 months.  GC really died off after launch.