As much as I wish that were the case, no, unfortunately many people (including leadership) at these organizations assign non-trivial odds of extinction from misaligned superintelligence. The arguments for why the risk is serious are pretty straightforward and these people are on the record as endorsing them before they e.g. started various AGI labs.

Sam Altman: "Development of superhuman machine intelligence (SMI) [1] is probably the greatest threat to the continued existence of humanity. " (https://blog.samaltman.com/machine-intelligence-part-1, published before he co-founded OpenAI)

Dario Amodei: "I think at the extreme end is the Nick Bostrom style of fear that an AGI could destroy humanity. I can’t see any reason and principle why that couldn’t happen." (https://80000hours.org/podcast/episodes/the-world-needs-ai-r..., published before he co-founded Anthropic)

Shane Legg: (responding to "What probability do you assign to the possibility of negative consequences, e.g. human extinction, as a result of badly done AI?") "...Maybe 5%, maybe 50%. I don't think anybody has a good estimate of this." (https://www.lesswrong.com/posts/No5JpRCHzBrWA4jmS/q-and-a-wi...)

Technically Shane's quote is from 2011, which is a little bit after Deepmind was founded, but the idea that Shane in 2011 was trying to sow FUD in order to benefit from regulatory capture is... lol.

I wish I knew why they think the math pencils out for what they're doing, but Sam Altman was not plotting regulatory capture 9 years ago, nearly a year before OpenAI got started.