It always amazes me that companies never offer more plain vanilla index funds. I have seen VINIX (S&P500) but I have never seen anything for Dow or Nasdaq or other kinds of index funds.
Most companies these days have target date funds which are a blackbox and you don't know how they will do.

Why not offer more cheap index funds along with their usual catalog?

I think it is mostly about $$$ and fees. Our company got bought several years ago, and I'm very happy with the parent company's 401k plan. My entire portfolio it split across the following Vanguard funds:

Institutional Index
Total Bond Market Index
Total International Stock Index
Mid Cap Index
Small Cap Index