To the second question: since each mission is expensive and time-consuming, scientists reasonably want the best sensors for each mission. That's both the tech

To the second question: since each mission is expensive and time-consuming, scientists reasonably want the best sensors for each mission. That's both the tech upgrade during the n-year coast phase, and the investigation upgrade as they work out new things to investigate. It's not as straightforward as spamming the system with cameras. That's bound to happen more, after the MarCO cubesats had success flying along with Insight.