Dentures for periodontitis

So I have a question about periodontitis and taking dentures.
I know that the common treatment for periodontitis and deep pockets is to regularly clean them by the dental hygienist and of course brushing, flossing and such yourself. And if that doesnt work then there is flap surgery.

But I wonder why are dentures not recommended? Wouldnt that solve the issue? Why do dentists all are of the opinon that keeping your own teeth is so important?