According to physics doesn't it say that lesser the are greater to force or grip. So why wheelies performed on tyres with greater thickness?
Tricks in general are often done on bikes with fairly wide tyres, so that might be why you're seeing wheelies on such bikes. They can be done in other bikes though. One of my riding buddies is prone to doing wheelies on his road bike, though he's old enough to know better.
In general, on a dry road, all bike tyres have plenty of grip, but bikes designed for wider tyres tend to be tougher and more suited to the landing (which would be rather harsh if your front tyre was 23mm and 7bar.