No parts, no machines to make them, so they'd need to design from the ground up. They'd need to train new folks to fit these new revolvers. They may do something similar, they've got the Cobra afterall, but who knows.
I worked at a shop when they introduced the Python Elite, all those guys that said Colt should make a new Python then bitched and moaned about the price and quality and everything else. They sold like crap, though now they're pretty expensive too.
Ignoring everything they'd need to get a Python up and rolling, look at the Single Action Army. They DO make them, they have parts, they have machines. They can sell all they can make, but they don't have the capacity to make enough of them for the market. If they can't increase production on a current product to meet the demand, adding a new product will have some corners cut.