I don't agree that the orchid should be thrown away. If you are attached to it then look after it and it should be alright?
I have had loads of rootless phals and none died... six months from now they'll be ready to bloom and it will be like nothing ever happened. In fact, all the broken and old roots are gone and your new set are all shiny and new! The first leaves grow in tiny and the next set grow to a fairly normal size. When the roots grow in it will happen rapidly.
I keep mine in bright light or even under artificial light if available to speed this along. Some people say low light is best to avoid stressing it but I want the new roots as quickly as possible and give it bright light. It's controversial which is the correct way so just do what you think is best.
Sometimes we buy orchids that are more valuable/rare in poor condition and having the skills to turn them around can be quite handy. I like to experiment on growing my orchids in different ways and sometimes it goes great and sometimes it goes wrong. Sometimes overpotting or changing media can result in a rootless orchid quite quickly... not good, but not the end of the world either.
If I tossed out any orchid that had a poor root system or a hiccup along the way I wouldn't have many orchids left. I don't think there has ever been a time when every orchid in my collection is thriving or in great health. There is always an orchid or two struggling along but with a bit of patience it will be fine!!
I don't bother with incubators or bags - just put it in moss/semi hydro or even just put the base in a glass of water to just below the green part!!!!
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