If the plant is healthy, it should get a keiki (or more than one) on it's own - the plant will want to survive. It can also still bloom if there are leaf axils that haven't bloomed. I had a Phal that grew a terminal spike, the main plant bloomed a few more years, and it also, not long after the terminal spike, started a new crown just below the original, which bloomed after a couple of years. So, it's worth taking care of the plant if you like it :)

I did the same thing! I purchased a mini phal (NoID) with a terminal spike. I allowed it to bloom, but when it was done, I cut the spike all the way back. I continued to care for the phal as I care for my others (weekly watering and feeding, etc.). In 9 months or so, it has since grown 3 new leaves from the crown + a flower spike. I don't know exactly what it is? At first I assumed it was a keiki, but there are no roots growing from it. The plant (or mother plant?) has been putting out new roots as well and looks fine. I'm not complaining, just wondering what it is I have here?

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Here's an album showing my phal from all sides. All new growth is lighter green, and you can see a new root emerging. If you look closely, you can see the dried stem from the terminal spike. It emerged from the center near the stunted leaf. Thanks so much for your interest!

https://goo.gl/photos/qg6qFScTi7zagH7h6

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That's what I assumed. I guess what I'm left wondering is:
1. If it's a keiki, wouldn't it have put out roots?
2. If the mother plant is terminal, would it continue to put out new, healthy roots?

Thanks so much for your answers! I've only been doing this for about a year.

This is my terminal spike Phal. As you can see, the old plant is yellowing. This has been a very slow process, and the original is, I suspect, dying away. The yellowing has been slower than when they drop their bottom leaf.

https://c4.staticflickr.com/6/5805/3...154e3d196d.jpg

But, the new basal keiki looks great :D

I try not to see it as the old plant dying, rather, just continuing to live on in a new, "healthier" form. Terminal spike or not - between them they have the best roots of all my phals. Some of my phals take off but others just struggle through life.

To cut to the chase, I think the question is, "Will a Phal that produces a terminal spike die? Stuff I read on the Internet says it will."

The answer is, "It will almost always push out another growth and survive."