According to Sensor Tower volumes Snapchat has no signs of desperation.

Rebranding usually has nothing to do with desperation or failing products, more likely with a different market positioning.

Snapchat could be sold tomorrow for around 15 billions with just 330 employees. To me this looks pretty successful !

Snap Inc (widely known as Snapchat) is moving towards hardware and wants to be known for being a camera company.

It like Google rebranding itself as Alphabet and becoming a smaller branch of the whole company.

Snapchat is not a failed product as they plan to move to IPO their brand for a value of 25-30 Billion dollars (that's a unicorn value).

Regarding their hardware move, they are setting up a Research & Development (R&D) office in Shenzhen, China, a global manufacturing hub that brings in

Since it’s main strategy is to acquire startups that lines up with above goal.

See the list of acquisitions here:
Snap Inc. - (Source: Crunchbase - https://www.crunchbase.com/organization/snapchat/acquisitions)

Areas of interest include wearable and flying cameras with names like Narrative and Lily Robotics having been part of discussions.

Feel free to ask more about Snapchat or Snap Inc. I really am BIG on the platform itself.

Snapchat: StringStory

It is a name change to embody the company's vision and intent to expand beyond just their flagship product (mobile app) and what they're known for best.

Not sure why a rebranding would directly imply failure.

I believe it's just brand. They built it when chat was super hot (Whatsapp specially was the pioneer to create a huge hype) and now they became a verb. Stay close to your customers/users and listen to how they use you.