When not governed by focused adults NASA evolves in to a "big science" clearing house; the "funder of last resort" for all things "science." In part this is because the agencies these projects should inhabit are huge lawyer farms with zero engineering capability and an active aversion for such. Allowing NOAA/USGS to fob these projects onto NASA only fosters this anti-pattern.
You see this pattern in other agencies as well. One learns from Madoff transcripts that the only actual mathematician the SEC involved in the investigation was a part-time adjunct professor — whom the lawyers studiously ignored. Same thing during the Toyota SUA hearings; the NTSB lawyers couldn't name an actual automotive engineer in their employ or cite even an approximate figure for how many they might employ. I still don't know if they employ any. All I know is that when they needed answers they called NASA....
Where overlap is inherent NASA can be contracted, but most of what Earth Science actually needs from space (satellite design, launch services, big data, etc.) is available at lower cost from commercial providers — approximately the same providers that launch satellite TV systems.
The climate fear mongers will never accept this. The truth is they covet the "NASA says..." credential. NASA is still perceived as a neutral agent, despite the best efforts of Hanson et al., so NASA generated science isn't as easily dismissed as agenda driven science from inherently agenda driven agencies.