Why is Blu-ray referred to as "Sony's format?"

[Zixxer]

Why do you think everybody calls Blu-ray "Sony's format"? Consider this literature from [I]Wikipedia[I].

1. The "Blu-ray Disc Founder" was founded in May 2002 by nine leading electronic companies: Matsushita, Pioneer, Philips, Thomson, LG Electronics, Hitachi, Sharp, Samsung, and Sony.

2. Blu-ray was developed by the Blu-ray Disc Association, a group of companies representing consumer electronics, computer hardware, and motion picture production.

I know Sony is one of the larger companies involved, but there are some larger companies listed above.