Vitalik B. In a recent blogpost: basic layer of Ethereum should be stable and simple, complex functions to be pushed into layer 2 and above. Even smart contracts (la raison d’être of Eth) to be serviced by ‘Execution Engines’ in layer 2:

—“Note that anyone can create a layer 2 execution engine at any time, different users can use different execution engines, and one can switch from one execution engine to any other, or to the base protocol, fairly quickly.