Perhaps, perhaps not. It's best not to speculate on these things, as Westerners are notoriously terrible at guessing Ghibli's intentions. Every Ghibli movie of the last 15 years is heralded as "Miyazaki's retirement," for example. But next summer will be a critical milestone for the studio, as it completes its "Five Year Plan." This plan introduced the next generation of feature film directors, while Miyazaki prepares to move to a more background role. Can Studio Ghibli survive in a post-Miyazaki era? Would the public accept the new directors? Fortunately, The Borrower Arrietty and From Up on Poppy Hill became hits, and Goro Miyazaki is already in the planning stages of his next film (a samurai period piece).
Although no official word has been made, it's entirely reasonable to me that "Bamboo Cutter" and "Kaze Tachinu" will be the final directorial feature films by Takahata (75) and Miyazaki (71). Advancing age and the long production times necessary for feature animation almost requires it. The time may be coming for Studio Ghibli's legendary founders to take the stage one final time.
Mind you, this is only my speculation at this point, so don't quote anything as the Written Gospel. But I think this is where Ghibli is headed, and I wouldn't at all be surprised if Toshio Suzuki's plans involve this in some fashion.
Here is the translation from Suzuki-san's radio show, provided by T. Ishikawa and posted on GhibliWiki:
One of the guests asked Suzuki a question near the end of the radio show.
Guest: When is Takahata-san's film released?
Suzuki: Well, Miyazaki... (narration is inserted on top of Suzuki's voice)
Narration: Sorry, we cannot yet broadcast this talk, but, actually Suzuki-san seems to have an incredible plan which is not swept irresistibly by the current of the times.
Guests: Wooooow! (Guests are astonished by Suzuki's plan)
Suzuki: I'm so sorry, but we make all of next summer into Studio Ghibli.
(Laughter and the applause by guests)
Narration: Probably, Calcifer's flame begins to blaze like a brick from now on.