It might be, I don't know. In practice (that is, in carrying out cryptographic attacks on real systems), nobody ever cryptanalyzes ciphers, so I've hardly studied block cipher cryptanalysis at all; someone much smarter than me gave me a purely linear block cipher once and I didn't spot it (plus side: now I can break purely linear ciphers! make a bunch of them! put them in JWT!), so this stuff is generally over my pay grade, though I have cryptopals exercises for basic linear and differential cryptanalysis tee'd up.

But I'm just noticing how many named cryptanalytic techniques, like Boomerang, Impossible Differential, even I guess to an extent Slide, are really extensions of Matsui and Biham and Shamir. And that's true of C/C++ software too: most attacks seen in the wild are derivatives of just a couple basic techniques ("out of bound write" is obviously putting my thumb on the scale, but "buffer overrun", "integer mishandling", and "use after free" cover a pretty good fraction of all attacks on memory safety).

Which is all to say: "we've had no good ideas since differential" might not be as meaningful as it sounds? Or maybe it is. Sometimes the best way to get good information into a message board thread is to add bad information, and, in theoretical cryptography, I contribute that ably!