And how would you propose that Paizo be an early adopter, when they still don't even know on what terms they would be allowed to write 4E compatible products? WoTC took that option away from them.
As for lost customers, as things stand now Paizo may end up inheriting the base of people who want to stick with 3.5. Even if that's 10% of the total, it's a huge win for them.
And like the previous poster, Paizo's decision to stick with 3.X makes me less likely to switch to 4E. Their adventures were by far the best of the 3E adventures , after all.
Ken