Disappearing middle layers:
The OP mentions "backendless applications", and using Javascript and the browser as your platform feels like the same kind of trend.
Sure, all those layers are still there — OS, TCP/IP, raster — but we've settled on a standard simplified foundation that's good enough and that everybody implements, whether it's Safari-iOS-touchscreen-ARM-LTE or Edge-Windows-mouse-x86-Ethernet.
"Static web applications" likewise — maybe instead of your own backend you call a few SAAS's that you've configured in a GUI rather than written code for. The point is you've reduced the number of layers you have to maintain, while still targeting a huge number of users.
In general, the trick is settling on a foundation. The web has evolved rather than being handed down from on high. What consensus will the next 5-10 years of evolution bring? Or will new platforms appear? Will Fuchsia show up and look a lot like the web?
Maybe the quality of that foundation can be measured by programmer productivity. A web standard that's consistent from device to device is a boon to the whole world. Thank you MDN for telling me what works, and where! https://developer.mozilla.org/en-US/