I have not experienced this as a big problem for teams. There are many ways to collaborate, iterate, capture, and communicate ideas other than whiteboards, and people naturally find and adapt such methods based on their remote culture.

In fact, whiteboards, imo, are not particular good for this as they require everyone to be present in one place at one time to participate, you can add links, you can't capture side comments, there is no edit history, etc...

We use Google Docs heavily to capture rough ideas, blast them out, get comments and input, and iterate. If we decided that we would benefit from the input of someone that we did not anticipate, it's trivial to send them a link and ask them to comment when they have a chance. Those docs often get thrown away after they served their purpose, in the same way that a whiteboard gets erased.