Is this Crimson Pygmy Barberry dying?

For over 20 years, this barberry bush has been a prickly feature in the garden and was, until perhaps 5 years ago, looking like a proper thick bush. These days however it looks more and more like a few twisted branches and twigs that don't resemble much of a bush. There was a front branch but that section died off, as well as that at the back right. Now, the larger left section looks less than happy although there are several fresh areas that have sprung up in the last few years and look ok.

What's the consensus? It's getting progressively worse but what to do about it I don't know. Chop it right down? Give up on it? It's looking an embarrassment and a pale shadow of it's former thick lush self. I think it's on its way out but is there anything one can do to help it? Lots of the bark looks crumbly the lower down you go but I'm thinking that normal.