1.	We've seen this many times. The Apple II became a cluttered mess of upgrades and add-ons, which begat the relatively wide open spaces of the IBM PC. I remember thinking that 640K of RAM was enough for eternity. Four years later Lotus 1-2-3 had filled the memory, and the PC floundered with incompatible approaches to overcoming the memory limit.
2.	Along came the Mac, with its linear address space and a non-Intel processor, it took hold, and it was time to convert character-based software to the graphic UI that came with the Mac, and later, Windows. Many leading products, including WordPerfect, dBASE and 1-2-3 were left behind in this transition.
3.	Then in 1993, the web caught on and rewrote the rules. The graphic UI was thrown out and then hasitly and unsuccessfully added back (Java). Individual operating systems took a back seat, and HTML replaced the more expressive screen display technologies on Mac/Windows.
4.	With the web, we took a big step forward, networking became part of the user interface, but we also took a big step backward as lineto-moveto was replaced with HTML's more clumsy <blockquote> and <table>.
5.	So, in this context, Nielsen has, in my opinion, devised the math that proves that we're about to make another of these transitions.