How is that morally different from your contribution being used by non-contributing companies to turn profit. The existing codebase stays OSS, and can be forke

How is that morally different from your contribution being used by non-contributing companies to turn profit. The existing codebase stays OSS, and can be forked. The work they put in starting now, is going to be proprietary for three years. It feels like a stupid change anyways, as companies can just keep using the old OSS version.