Here's a heavy old FE piston....
And here's a light Windsor piston....
Neither one of those are what I would consider "exotic". They are both custom pistons from Diamond, and the FE piston is for a 4.125" stroke, which makes it taller than the pistons I would use for a 4.250" stroke build.
You will notice that the Windsor piston has a pretty substantial 30cc dish in it, while the FE piston has a small 14cc volume. You can also note that the Windsor piston uses a support rail, which adds to the piston/ring package weight.
The FE piston could have been made extensively lighter.
Just one piece of the puzzle of course, and rod design/weight makes a pretty substantial difference in itself, but it's easy to see that you can cut down big block reciprocating part weight without a lot of effort.
I would also suggest that the non-builders here look into the difference between "rotating weight" and "reciprocating weight", which we use to both balance and to pick lightweight combos for race applications.