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.
But, the new basal keiki looks great
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.