Same thing that people did when looms took over the textile industry. When the electronic computers took over for human computers. When switching circuits took over from telephone operators. Move on to the next job that machines cannot do.
In the late 1800's 70-80% of the US workforce worked in agriculture. Today that number is 2-3%. If mechanization was going to leave people without jobs it would have already happened.
Of course the naysayers will cry that not everyone can be an x, y, or z. But why should we expect to know any better what the future holds than people of the past. If you had told some farmers in 1863 that in 150 years almost no one would work in farming and that millions of people would be employed as web developers they would think you were insane.
Mankind's desires have no limits, it is only our resources that constrain us. There will always be something. Even if that something is handcrafted hood ornaments.