SpaceX, OpenAI, Google etc. - they're all asking for billions from investors. Where is it gonna come from?

SpaceX, Anthropic, and OpenAI all want to IPO soon. Google is selling a new round of $85B worth of stock. So we're easily looking at hundreds of billions of dollars into AI. Importantly, this is new capital, not buying and selling existing stocks. So where will this money come from? Most importantly, will this money come from investors selling existing AI stocks? Is this what we're seeing now? If so, is it time to pull out for a few months and invest somewhere else entirely?