One of the better posts on this site! Thanks for your logic. Coinbase is not Mt. Gox. It has MILLIONS of dollars of Venture cap money funding it, it is HIGHLY regulated, and it is located in the USA.  With that being said it does appear they completely messed up the ETC situation. They should have just credited all their ETH holders with ETC, but it appears the ETC may have been stolen from them through a replay attack, or multiple replay attacks that they either ignored or did not care about. They definitely need to fix some of their businesses practices or they will run out of venture cap funders.  They are raising fees for credit card users.  This is a fact. The rumor of their insolvency may have caused some major BTC holder to sell resulting in the price drop. That is hard to tell. My latest cryptocurrency related post can be found here: https://steemit.com/steemit/@bitcoinmeister/real-cryptocurrency-concerns-inspired-by-the-bitcoin-group-show-they-need-a-marketing-panelist