It isn't so much that your employer is hiring (that's great!) - but what happens should the employee be let go or want to change employers? Are there other employers in the area needing software engineers? Are there enough of them to support the needed software engineers as a whole?

That's the issue, as I am sure you are aware. In SV, a software engineer (according to trite legend, I suppose) can walk out the door and be hired again across the street the same day. They can probably repeat that every day for a year, and still not run out of options.

I know that's an oversimplification, and hyperbole to boot - but you know what I mean.

An area needs more than one employer in the space to make it attractive to those employees they need. Especially if they want to stay in the area long term...