I think it depends on what you want to accomplish with the whiteboard. If you just want to capture a list of ideas, google docs will let people collaboratively

I think it depends on what you want to accomplish with the whiteboard. If you just want to capture a list of ideas, google docs will let people collaboratively edit a document or you could just have one person share their screen and capture verbal ideas. If you want to diagram things, pen and paper + a camera can be just as effective if not more effective than a whiteboard. Often it's better to have the whole team do a sketching exercise and share their results which isn't really effective on a single whiteboard. More importantly, whiteboards are never going to be effective for remote organizations for the same reason hallway conversations / voice chat aren't effective. It builds knowledge silos as only the people who were there understand the context of the whiteboard even if you photograph it.