Backend been stagnant for a long time, but advanced packaging, which I count separately from it, was really hot, and few people noticed that.
The total global demand for packaged chips isn't growing much because more, and more electronics is using microcontrollers, and SoCs which replaced tons of discrete components. And with each year, the BOM reduction is getting more, and more serious.
Take apart a 200X wireless computer mouse, and a 202X wireless mouse. There may be an up to 20-fold IC BOM difference.
On top of that, smartphones massacred MP3 players, cameras, remote controls, home AV, POS terminals, radios, and walkie talkies, and god knows how much more things.
And the highly anticipated IoT is not helping, to the big surprise of market forecasters. The "Smart Home" section in BestBuy been known to be a freezer.