Assuming you're replying to CrystalFantasy, this person you're replying to isn't on to anything.
Cambridge weren't forced to develop for Vita or PSVR, they chose to make games for those platforms, plus they even made games for basically every other Sony device and technically RIGS has to run on PS4 to play, but their titles didn't sell well for the most part, yet Sony still kept them around since 1997.

Media Molecule have had great success with LBP 1&2, Tearaway sold well for a Vita game and Unfolded didn't require more than a small fraction of the Studio's resources to be made, so it's sales didn't need to be that high to be considered a success.

There's every indication that Dreams will do very well with it's target audience, hell it's going to have a huge core adventure, as well as be the evolution of the creative style of content the Studio have become famous for. You can basically make anything you want digitally, which will mean Media Molecule can create a tonne of content, along with the game's core audience being able to expand the game's universe in a seemingly endless way.
If content creators can make anything from any game genre, their own assets, animations, movies, music and so on then the possibilities are quite literally only limited by the creator's imagination (and current processing/RAM limits).

Media Molecule aren't stalling, they began making the tools to make their game, but that was a long undertaking because they didn't just want to slap a game engine, asset rendering, audio maker and content editor into a basic package, they wanted to make all of that work seamlessly together, while also being fun to use. They started actually building their core Dreams game when they revealed Dreams to the public at E3 2015.
BTW Media Molecule are a smaller studio than Guerrilla Cambridge were, by a good 20 people, so MM's costs are quite a bit lower.
MM may also be working on something else besides Dreams, since content creation is very fast with the game's tools. They could be building multiple games with Dream's tools.

@ ruefrak

I fear the same for Media Molecule. Tearaway on Vita had less sales than Killzone Mercenary at the end and the Tearaway Unfolded on PS4 bombed saleswise really hard. Dreams failure in sales could be the last straw.

In turn, I feel that since RIGS was a VR game that missed sales targets, Sony London and the Machester Studio's new VR games better make some decent numbers or Sony will pull out of the U.K. altogether and avoid such high taxes in the process.

Technically Cambridge were a part of Guerrilla, but how closures effect staff employment within the wider publishing company depends on the individual people getting laid off, whether they want to join another studio within that pubs family of devs or location, because maybe people can't move their lives to another part of the country or another country entirely for a new job, families may not want to move to London if they're happy in Cambridge and the dev may not want an almost 3 hour round trip every day to get to and from work.
Nearby studios may not need your particular skill set.
In some cases maybe developers don't have the budget to hire someone new.

There could also be issues with a developer, maybe they have a bad reputation and only had employment within Sony because of their longterm experience at that one studio and it was only that studio that were happy to put up with that person's ways.

Things aren't always clear cut and easy to work out because we wish it.