Elon Musk's trillion-dollar-plus SpaceX isn't a public company yet, but its size and ambitions are already upending the stock market and sparking questions over the power and influence wielded by such behemoths.Why it matters: The IPO, expected next month, would signal the start of a new AI era for the public markets, potentially valuing SpaceX as much as $2 trillion.The big picture: OpenAI and Anthropic are also expected to IPO this year — possibly translating into $5 trillion in value in the m...