Well, it’s clearly not a good strategy since it’s what allowed OpenAI & StabilityAI to get all the credit.
1) Allow publishing everything including source code => this helps the competitor directly. Bad move.
2) Disallow publishing => the researchers will be tempted to switch jobs for their competitor, since staying at Google will hurt their career. Bad move.
3) Allow publishing, but disallow everything else => this helps the competitors a little, but not too much. The researchers get credit for their work, which removes any incentive they have at switching jobs. Seems like the best compromise.
At least, that's my speculative take on this. Sure, OpenAI & StabilityAI get the credit in the public's eye, but there are also other incentives at play.