I don't believe Media Molecule's job at SCEWWS is to create games. Sony bought them on the strength of their Crate, Share, and Play expereince. I think Sony is looking to them to build creative software tools, that the PlayStation community, Developers, and App creators can use to build PlayStation exclusive content. Basically Dreams is the ideal game under John Kodera's microtransaction push at PlayStation. Get as millions of people making content on PlayStation, and selling it through PSN.
Media Molecule will no doubt continue to support Dreams with updated and expanded creation tools. Likely offering new in house creations to show off the advancements, as the new tools release. Still the main focus will be on developing the creative suite of tools.
At the end of the day, we will no doubt see great gaming content come as a result of Dreams. Some will be from Media Molecule, some will come from other SCEWWS teams, some from 3rd party publishers, but the largest will come from the community.
Obviously monetisation will be an interesting point for this game but I doubt ppl are going to pay for creations from other ppl tbqh. I think the creation stuff stays free but you possibly need ps+ to access it