The promise of quantum computing isn't to break encryption, that would make it a pointless billions-dollar Y2K-like makework project to reconfigure all our systems to use post-quantum cryptography schemes. Quantum computers are primarily interesting because they promise to get a "native" speedup at simulating quantum-mechanical objects like molecules and proteins. So drug & material design could benefit. However, the field has been stalled for the past decade.
I do disagree that technological advancement has hit a wall, though. Things are moving faster than ever. To choose a single example, the impact of cheap energy-dense lithium batteries has been enormous. Displays also really have improved a lot.