When industries are young, there are a lot of different solutions to their market's problems.
As industries mature, the solutions to their problems start to look similar.
Eventually, the best solutions become expected standards.
The market will adopt what's familiar more quickly than what's not. So, products that leverage common patterns have a greater chance of success.
Jakob's law states:
Users spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know. — Jakob Nielsen
Mobile and desktop interfaces show some indications of this convergence across the board.
For example, mobile buttons are wide, rounded rectangles.
Desktop nav bars are placed at the screen's top left or right corners. Desktop sidebars go on the left side of the screen.
Mobile nav bars and tab bars go at the bottom.
Desktop quick search popups are centered and float above the rest of the content.
There are many more, but you get the point.
Convergence is good
Hundreds of years ago, humanity agreed that books should have a thicker front and back cover protecting multiple paper pages printed on both sides of the paper.
The format of books is universal, but the variety of information you can find in them is unquantifiable.
Similarly, I believe once we settle on well-accepted formats for mobile, desktop, and wearable devices, we'll be able to spend more of our energy on the actual content of the application.