The following quote from a senior member of the DUP suggests some people believe so.
Nigel Dodds: We need a willing partner - some of us fear SF have decided the time for devolution is over
I analysed Sinn Fein tweets over the Easter period, from 25 tweets over the Easter weekend:
Irish unification/reunification was mentioned 13 times
Brexit and the EU were mentioned 5 times
the talks process was mentioned once
Stormont was mentioned zero times
The DUP are mentioned twice, on both occasions they are mentioned with the British Government as if the DUP and the British Government are the same thing. On both occasions the sentiment is negative. It is not surprising that a Republican or Nationalist party talks about reunification of Ireland, escepcially at Easter, but the Sinn Fein Twitter account definitely gives the impression of a party that has given up on the devolution route and instead is returning to their roots - a 'united' Ireland with or without Unionist engagement or approval. Just as the unionists have done little or nothing to win over soft nationalsits to Unionism, Sinn Fein have had zero success in convincing unionists they would be better off in United Ireland.