History has shown that with time these numbers shrink, there will come a time when the difference is between two very small numbers and that won't be a factor. It almost is. A couple of years. 4G LTE for example.
That said, I hope you're right. A world in which front vs. back end didn't matter with respect to time would be one in which developers were free to reveal far less on the client side, and that would be a victory indeed!