It's not just the public who are an issue though Headbanger.
Promotional budgets rely on saturating print media, tv, radio, internet, and so on and so forth, in order to push a new release. There is only so much space in any media to promote new releases, so in order to avoid an overload, and therefore some releases receiving less attention, the record labels will prioritise their guarenteed big sellers, and 'bump' others back in the schedules, hence the several promised, and then delayed release dates.
Enjoy your album when you eventually get it!