Hiring only senior engineers is a terrible policy that will kill companies

Rocket science wouldn't be nearly enough by itself.

Computer science and associated software development is a science of its own, it just doesn't happen to be a natural science. Lots of math can help, and it's still largely unexplored with more discoveries to make like any other, and advances go hand-in-hand with the progress from the materials and electronics people.

I enjoyed working with some juniors until I "retired" in natural science, but I'm continuing as a training consultant. It's actually fun because there's so much to learn that people come real far real fast. And quickly realize how it's going to take years to really get good, but it's got to be kept inspiring to avoid discouragement, and the enthusiasm shows.

Organizationally, for people not that many years out of college, I think it's best to have a ratio of seniors who are cool-headed cats themselves not just to set an example, but willing, able, and technically superior enough to be able to herd cats and are in position to do so.

Who better to be carrying around the tunafish when you want a whole team to be moving in the same direction?