Viable, absolutely.

Are current valuations correct, though? That's not nearly as easy a question to answer. If in reality Snapchat is worth $8b, not $16b (current market value), then $8b of capital gets destroyed the moment everyone realizes the "true" value. Now, repeat that process over every highly valued and highly leveraged tech company that exists. Many billions of dollars could cease to exist in a short matter of time, which would impact bonds issued by, and loans taken out by, these companies, the bond market more generally, and the stock market.