Some other stats to ponder:
I own a 2002, 2005 and 2011 4Runner. So one of each of Gen 3, 4 and 5.
2002 - 3.4 V6 5VZ-FE, SR5, curb weight about 4,000 lbs
2005 - 4.0 V6 1GR-FE (single VVTi, SR5, curb weight about 4,200 lbs
2011 - 4.0 V6 1GR-FE (dual VVTi), Trails Edition, curb weight about 4,700 lbs
With each generation there was a pretty big increase in size/weight from the previous. They all have Automatic transmissions and they all are part-time 4WD systems. They all are running Michelin Defender LTX tires. They all get used in mixed driving conditions so these mileage numbers are a relative apples to apples comparison for my driving conditions.
2002 = 19 mpg
2005 = 20 mpg
2011 = 19 mpg
So if the new US Land Cruiser (which is a rebadged 250-series, more in the GX/Prado/4Runner size class) gets 23-25, I'm impressed.