Tundra 5.7 Owners

I'm subscribing to hear real world 5.7 Tundra numbers. I'm a Toyota truck guy, I'm on my 3rd one which is an '04 Tundra Limited 4x4, 4.7L engine, 4.10 gears. While I don't think anyone buys a truck to get good gas mileage, I feel like Toyota is really behind the curve on mileage. Mine sucks, 8-9 towing (which I know is typical across the range of gas engines) and 13-15 mixed city/highway. 17+ if all highway. If that's all the better I'm getting, what's the point of the small V8 and sub-1500 size? Newer domestic trucks seem to float around 20's for mpg on the highway and upper teens with mixed, but the 5.7 Tundra is known for being a fuel hog. My current truck is marginal for our towing needs so I'm going to be getting a new TV in the future and would like to stick with Toyota, but the 1500 diesels and/or Ecoboosts just seem like such a better deal for fuel mileage. To be honest I think I might be going with a full-size SUV for the next TV based on passenger hauling, I'm interested to see what the future holds in that category.