The critical view is that these IPOs are bumping up against physics. How many trillion dollar companies can the economy support? The US GDP is roughly 32 Trillion. A company with 100 billion dollars in revenue and 10x annual growth would be expected to increase the size of the economy by 3.2% in its first year, and about 30% in it's second year post IPO existing.

While we could claim that such a company can grow by consuming a larger share of the GDP ... this would not bode well for future political stability, and nationalization would be a major topic.

So your left with a fast take off scenario, a job apocalypse, or a massively reduced growth rate.