There is a perfectly centred hole in the Frunk for water to drain into the nose area; that at least works to a degree. Also, the question was indeed whether the tube connecting the one in the channel and the frunk hole was missing, however if so many are "missing" I will have to conclude that there never was one. I have seen numerous cars with odd rain channels: look at the 60s Mustang rear screen area drains for example.
I'm with you. Seems way too many X's have rot in the front nose cover, forward hood lip, channel. And looking at how that rot migrates, it appears to begin at or around the channel in question. Which suggests water must collect there. So providing a drain may help, if it is designed with a path to exit as you suggest. However I think the other option of protecting the area like @NEG just described may be sufficient also. Fortunately I don't have to worry much about water runoff here, but even my X (with original paint) that has lived its entire life in this desert has the beginnings of a little surface rust there after 45 years. I'll take care of it when I repaint the car.
All thoughts are very appreciated: today I put a bead of plumbers sealant (no seam sealant to hand but this will do the same job) along the front seam in the frunk, arranged some rain catch containers in that area, temporarily covered the channel hole as an experiment and gave one coat of anti-rust paint to the channel. Next the Waxoil and then......investigate a better exit route.
