I disagree with the why, but sure, let's go with that since it's not really important.

Why could we make those great leaps then and not now? What changed?

How could you disagree with cheaper, smaller, faster, more battery efficient hardware led to WiFi, Bluetooth, modern smart phones etc?

But why nothing as ground breaking - physics.

At a certain point you come up with speed of light limitations and other sub atomic interferences that are way out of pay grade when it comes to producing smaller processors.

The industry keeps coming up with new techniques as far as wireless communications. But eventually again you come against physics, certain spectrum is worse for communications and Shannon-Hartley theorem.

With cameras, you can only do so much in a phone form factor. You can also only do so much with current battery technology, heat dissipation vs power etc.

And a lot of the technology is “good enough”. There is only so much video and audio fidelity that you need to reach the limits of human perception.

What exactly break through technology are you looking for?