Comparing the processing ability of the human brain with that of Watson is not meaningful. A computer also regulates a ton of parameters like CPU temperature, voltage, and so on. And every single unit has its own logic circuits for regulating internal stability.
What's meaningful is comparing energy and time required for creating a human or a computer capable of doing this, as well as maintenance costs.
And assuming Moore's law continues unabated, a Watson-scale machine will be competitive with a human within five to ten years. Given that it's already functional, I would bet money that it will be cost-effective compared to Ken Jennings by 2045, whether through advances in computing or energy. I wouldn't bet it will be sentient, but just that we can build one and set it up to answer questions cheaper than we can raise someone with as good a head for trivia as Ken.
What's meaningful is comparing energy and time required for creating a human or a computer capable of doing this, as well as maintenance costs.
And assuming Moore's law continues unabated, a Watson-scale machine will be competitive with a human within five to ten years. Given that it's already functional, I would bet money that it will be cost-effective compared to Ken Jennings by 2045, whether through advances in computing or energy. I wouldn't bet it will be sentient, but just that we can build one and set it up to answer questions cheaper than we can raise someone with as good a head for trivia as Ken.