Maybe that's it. I consider that to still be in the range of "standard" as I see lots of tables with thicker tops like that. All relative I guess.
Either way, jjm, there are several ways to achieve the look of that top. How heavy do you want it to be? How much work do you want to do? What tools do you have? What is your experience level? Lots of options.
Personally, I'd just use some 6/4 wood and join it up at that thickness and route/plane to the shape I wanted. Or you can just edge band it with some thick wood with the majority of the surface being thinner, like Ryan suggested.