ChainsawAsh said:

As such, remember that the Nostromo was essentially a mining/transport ship, whereas the Prometheus is a heavily-funded research vessel. Of course the technology onboard the Prometheus would be newer and more expensive than the technology onboard a ship whose sole purpose is to haul shit from point A to point B.

Ash is on it. Any technical discontinuity can be applied to the fact that we're looking at two different classes of workers here. The Nostromo may very well predate the Prometheus.