Why did Pablo Picasso's self portraits worsened over time?

Why did Pablo Picassos self portraits worsened over time?
I know some people would say things like "beauty is in the eye of beholder" or "the pic on the right is the real art" etc. But I want to know why an artist would shift from being hyper realistic to completely deformed abstract?

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Why did Pablo Picasso's self portraits worsened over time?
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