I really don’t understand what you’re saying here. Letters have existed for literally thousands of years at this point and people were able to communicate effectively through that. Several countries were founded and destroyed with coordination through written communication.
I know plenty of people that still study the letters that were used to communicate while founding the United States. It seems to me that the last 20 years has led to a massive decrease in the effectiveness of written communication because people don’t have to be clear or concise anymore.
Perhaps they still study those letters due to the ambiguity in understanding of what those people meant?
We also don’t know that they understood each other as effectively as they would have if they communicated verbally in person.
It is far easier to understand someone’s true meaning in person thanks to tone and body language. Communication in person is quicker because typing/writing is slow. That speed allows for faster ideation and iteration.
It’s not impossible to communicate in written form at all but I don’t believe it’s as effective.
To your first point, we write more emails, more DMs, more online comments, more text messages etc than ever before. We clearly communicate more in written form now than at any point in history.