Financialization of the economy
Financialization is just a broad term for when financial markets become bigger and have more influence on the market economy.

I'd say that it wasn't so much markets becoming bigger that directly caused the 2008 crisis, but more that the shadow banking financial market became bigger (intermediaries not subject to the same regulation as normal banks). Financialization arguably caused the need for more niche ways of getting money into the market in this way, and as financial markets got bigger, particualrly in regards to housing, more banks ended up securitizing subprime mortgages, and that was a big factor in causing the 2008 recession.