The timing of all of this is much easier to pin to the creation and proliferation of capable of open weight models. Anthropic calling this out is not the cause for it; it's just an obvious correlation.
What’s changing now is that models are getting more powerful.
And no, before the labs there was a degree of fear for everyone to hack into some one else system. With the labs changing the narrative, anyone can just blame the agents for the breach, whoever did it would only get fame and no blame