F(x) = F(x) + F(x)

Eventually you hit OOM or some death limit even on a stackless language.

This is a memory leak now, not a stack overflow.

Thus demonstrating a finite stack. "Stackless" just a more efficent way to use memory. You could get the same things from dynamicly allocating and dealocating stack space as needed.

Put another way, allocating 1GB of stack space on a machine with 2GB of RAM is at worst the equivelent of using a stackless lanugage on a machine limited 1 GB of RAM.

PS: It's actually worse as stackless languages are stricly slower than actually having the equivelent stack space pre alocated and you need to put an pointer for each stack call pluss overhead for alocating memory.