There are microphones that can capture whispers and even subvocalization: https://youtu.be/NvVbCqDgfCs?t=520

The one demo'ed in the video is BOYA BY-GM18CU (https://www.amazon.com/dp/B0BF969RVP)

That one captures whispers. I've heard other devices can dictate based on vibrations from your neck/chest.

I've adopted voice as my main input, and i love it, It is much faster than text. and for your question, i do think NC headphones will become the default for open floor plan offices, or maybe microphones than captures whispers.

I can use my Macbook's microphone while my hifi system is blasting death metal at full volume. The people I'm talking to can't hear the music at all and still hear me perfectly. (The Macbook has multiple microphones in an array which can isolate the speaker from the surroundings.)

What's already happened to open-plan offices is that they are at least half empty due to remote work. People go to them to interact with coworkers as much as for a quiet space. People go specifically to be available for face to face conversation, so loud conversations are heard.

Voice isn't my main input but the handful of times I voiced something in the middle of an office, I spoke quietly, with a near whisper, into a close mic. It was much quieter than I would normally be able to speak to a coworker.

Along with noise cancelling headphones, noise canceling microphones will probably get really good.

tall, thick cubicle walls.