It makes a ton of sense to see this sort of joint effort being made by these enormous companies, but man, there's some part of me that can't help but feel grossed out knowing the best way to get the US to make the right choice is to have a handful of elite business people say it'd be bad for them.
Yeah, this letter is just proof of (the by now long standing fact) of corporate power/corporate capture of American governance. Tons of popular protests against big AI? Makes no difference. Joint corporate letter about big AI? Possibly the government will do something.
People unfortunately keep voting for “corporate power” politicians, so corporations continue to be in charge.
If you support the ideas described in Nvidia's letter, you're going against popular opinion. Most Americans do not want to "make advanced AI more accessible, adaptable, and widely available". Indeed, many areas of the country including the entire state of New York have enacted datacenter moratoriums, responding to the widespread public concern that we can't have too much AI or it'll drink all our water.