I have followed the great suggestion often given in this tread about requesting the return of the 17 inch on Apple’s MBP feedback page. I've done that several times over the past two or more years. I assume many other people have too. It doesn't seem to be working.
Perhaps we should think of supplemental strategies for encouraging Apple to being back the 17 inch. For example, suggestions on the feedback page probably are read by mid-level developers. They might be sent up to senior executives on occastion. It might also make sense to write to Apple headquarters, perhaps to the CEO or head of product develpment.
We also could try to get influential people to push Apple to bring back the 17 inch.
Furthermore, we could get articles published that use the carrot and/or stick approach. The carrot is saying what a great computer the 17 inch was. Bringing it back would help loyal Apple professioal and other users. The stick would imply that Apple was abandoning the professioal market or made other types of mistakes by discontinuing the 17 inch.
We also could compile a list of reasons for bringing back the 17 inch. Then our individual and collective arguments could have maximum effectiveness. Many great reasons for bringing back the 17 inch have been stated on this thread. These include use by professionals. Professional writers, photographers and others often find the 17 inch more productive. The presence of the 17 inch enhanced the whole MBP line, in part because it was considered by many experts to be the best laptop in the world, it was used by many professionals, and it often was shown in movies and television shows. Many people work in different rooms in their homes or offices, or in different locations. A large screen laptop makes it easy to move to another location and still have a professional quality screen. The 15 inch screen was made shorter and wider about 4 or 5 years ago. This is fine for movies, but bad for writers and others who view documents in portrait format. The 17 inch provides the extra height lost when the 15 inch was made shorter.
Another key point is that, in Apple stores, people who haven't used the 17 inch often have difficulty differentiating it from the 15 inch. But once people start using it, the difference in productivity and other areas becomes obvious. If Apple did a better job of promoting the benefits of the 17 inch, they'd sell more of them.
Re cost and technology, bringing back the 17 inch seems like it would not be difficult because they make a nearly identical smaller computer. Finally, many professionals would pay more for the 17 inch. I'd pay at least $500 more for the 17 inch if it were available. They could raise the price to cover additional costs. However, Apple has very high profit margins compared to other technology companies. Raising the 17 inch price too high might restrict sales. They probably do not need to charge that much more than the 15 inch to cover incremental costs.