Alot of people that play Brood War don't want to transition to SC2 because of a few things:
They believe it to be a better game
They don't have to upgrade their pc / buy SC2
It's harder to play
They prefer the original Battle.net
The epic long history of competitive BW
And the BW pros have been making so much money playing in Proleague / OSL / etc they have no need to transition to SC2, although with SC2 Proleague coming soon and Mike Morhaim talking to KeSpa again this might change.
I love SC2. It's my favourite game. But people are perfectly justified in preferring BW. Yes SC2 and BW are very similar but they are NOT the same game. That said I would still love to see SC2 evolve as a game and an eSport and watch some of my favourite BW pros that haven't transitioned yet light up the main stages playing my favourite game
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