>>5008783They produce and apply oils to their feathers when alive to keep themselves water proof. You would need to do the same thing to the feathers once removed from the penguin.
The optics of skinning a few dozen penguins to make one human suit would also be pretty bad. Don't think you'd stay in business for long.
Penguins shed feathers and regrow them as needed, how to you intend to replace 1 of a billion feathers on the suit as they get damaged?
As a civilization, we move towards lower operating costs and maintenance commitments. As someone said above, old suits were leather and required constant attention. Modern dive suits are made of synthetic materials and require a lot less maintenance and time commited to keeping them usable. A penguin skin suit would be a step backward.