HTML was designed from day 1 for exactly the role it is fulfilling today. The only difference is over time, the theology of how HTML should work has changed. Initially the idea was just to tag the information and allow the client device decide how it should be displayed. Along the way it turned into a WYSIWYG technology. Meaning the author needs the ability to define precisely how something has been displayed. Overall though, the change from HTML4 and HTML5 is not that dramatic. The biggest changes is the addition of the video tag, but that was done in a broken manner. So for a long time to come web authors will continue to use the HTML4 way of doing things.

As for FORTRAN. It's strongest use has alway been scientific programming. It was designed from the ground-up to be useful for that purpose, and has continued to be redefined with that end goal in mind. Weather forcasting is just one example. The biggest difference between FORTRAN and C, is FORTRAN is designed to optimize as much as possible, even at the point of possibly sacrificing what the less savvy programmer thought they were telling it to do. While C is designed to do exactly what you tell it to do, no matter how stupid. Lets take a simple example. Lets say you tell a computer to count to a million to add a time delay. The C program optimization might optimize the counting variables so it counts to a million very quickly. The FORTRAN program will just discard the whole counting operation, as it already knows the end result is a million. While a professional programmer can do the same level of optimization writing C, since few FORTRAN programmers are professional programmers, it is doubtful FORTRAN will ever be replaced.