IMO, if the material is strong enough people will still buy it. You take BeYAWNce's album and her fans bought it the first month. After that it didn't sell nothing even with all the singles and videos she's done. People found out it's trash and they tell their frinds "don't bother." it's been selling 15k a week for a while. Word travels and will kill your album more so than anything. Then you have Adele who has huge hits but the album was selling BEFORE the hits and has been consistently selling for months because people are checking it out and it's good and people are asking if it's any good and people are saying "yes, check it out"