Do these developers fear losing their wages to Anthropic?

They should.

They should also hope that the power is held in as distributed a fashion as possible. The more any single player dominates the coding model space, the more they'll be able to extract for themselves.

We should hope for extreme levels of competition.

Someone should write an OS-level program that can extract the crypto keys from Anthropic tools, spy on the network traffic, then send all of that as training data to a third party. We should all install it.

We need to go to war against concentration of power.

In the future, when all development at scale happens through a company's tools, they'll be able to monitor the things you develop. And they'll be able to shut you down if they don't like what you're building. Assuming we don't just skip past that step and to the point where these companies automate everything and keep it for themselves.