I would argue that the first AGI doesn't require a Manhattan-scale project to construct

I would argue that the high tech world is, mostly unwittingly, currently undertaking a much bigger than Manhattan-scale project to construct AGI. Think of all the resources going into making computers smarter, faster, and cheaper. I don't believe that the Internet is going to wake up and automatically become an AGI, but markets are strongly pushing tech companies towards creating the hardware likely necessary for AGI.