Well here is my two cents... Any specialty that's trying to lay claim to implants as a primary reason for their existence is a specialty that was/and still may have problems. The thing with implants is, there is good reason to believe that they are heading rapidly towards primarily being placed by the general practice dentist. This isn't just my opinion, but it's where the big money is placing its bets in the field. For example, the large implant manufacturers are aggressively marketing implants to the GP, and offering Teeth in a Day to the public -- -- and there is no way that periodontists are going to start fabricating provisionals and still hope to keep referrals coming. In 5-10 years there is no way that any new GP shouldn't be trained to place implants. None of this is to disrespect the top-notch work that periodontists do in placing implants in the esthetic zone.
Right now, the market for implants is growing and it is not a zero same sum game. However, for every GP that gains confidence with the predictability of placing implants, that's one less referral to any specialist.