Q: What happens when a bunch of companies ICO on the Ethereum platform?

A: They end up with a ton of ETH in a market inflated by speculation in the most volatile, non-vetted "private equity" market in existence. In the following months some of them start start selling off larger than usual amounts of ETH for operating costs, lambos etc.. then the rest of them feel the downward pressure and start selling as well. Did ppl think they were going to be able to rent offices with a bunch of ETH sitting in a wallet? This doesn't reflect on the intrinsic usefulness of cryptocurrencies, it just demonstrates that the sky is still blue and that free money usually IS too good to be true.