To me that is like saying that the failure of Microsoft Word to base itself on the standard 80 character per line standard is a glaring weakness of Word. Or that unicode suffers from the glaring weakness of not being based on the 128 character ASCII set.
If you wish to use 3-character (or longer as per many Unix) extensions on the Mac, there is nothing preventing you from doing so. If I download a file that you place on a website or post to a newsgroup, and you have given that file a “.jpg” extension, my Mac maps your pathetic and inefficient 3-character extension system to the much more flexible Macintosh File Type and Creator Type system, assigning your file the file type of “JPEG” and the default creator type of “GKON”.
As Wikkit pointed out:
On the PC platform, a file with the “.pdf” extension can be Adobe’s Acrobat portable document format (and that’s probably what you have the file extension registered as on your box) or it can be Microsoft’s package definition file, which is a text-based file used by some installers to modify the default installer behavior on a server. Because of the far fewer sequences available using the 3-character extension method, you’ve got this type of overlap, so editing a package definition file requires opening a text editor and navigating to the file rather than double-clicking it. Obviously the Mac world could contain overlaps since some fool could decide to use 8BIM as their newly minted program’s creator code despite the fact that Adobe Photoshop already uses that one, but because the pool is so much larger the likelihood is less.
And because the Mac system separates the concept of file type from the concept of file creator, I can set Graphic Converter (GKON) as the default creator for otherwise unidentified JPEGS but that huge JPEG of a very high-resolution aerial view of the site of the World Trade towers I’ve got that is beyond the scope of what Graphic Converter can open has the file creator of 8BIM and opens in Photoshop instead. And if you and I are both given a Zip cartridge filled with old WordPerfect documents filled with WordPerfect macros, and we both would like to open them in the modern version of WordPerfect rather than translate them into Word (which can’t run the macros), I can assign them File Type WPD4 and Creator WPC2 en masse with a couple mouse-clicks, and from then on when I double-click any of them they will open in WordPerfect, not Word. You don’t have that option – since both Word and WordPerfect use “.doc” as their file extension, your OS can have “.doc” registered for one or for the other but if you switch it to WP all your Word documents will try to open in WordPerfect instead of Word when you double-click them. AND…I can hand off the Zip cartridge to other Mac users and their computers will recognize those documents as WordPerfect documents, whereas even if you change the association of “.doc” from Word to WordPerfect, no other PC user to whom you hand the Zip cart will inherit that change.
Most Mac programs have the option of appending the appropriate 3-character extension to the file name for backwards compatibility with other operating systems.
So please elaborate on this “glaring weakness” of which you speak?