Because it's hard to do right. And, he said his first source was out, and had to start pretty much from scratch with a second source, who may have other projects to do.
Anything worth having is worth waiting for...and a turbo Zetec is worth waiting for.
BTW, thanks Karl for your help with my downpipe (back in the day). I liked the work the TP guy did for me...though he forgot to figure the wastegate would have a gasket. Oh, well...I made due