The way that this article is written reads like American propaganda. This is already being done, and has been done for a long time, including at the same or better temporal and spatial resolution. NISAR is genuinely cool, do I don't know why they felt the need to write this way. The new capabilities are mainly being able to do this in highly vegetated areas. In urban areas, like mexico city, this is literally 'intro to SAR' stuff.
NISAR is a realization of InSAR and SweepSAR techniques but done with dual radar frequencies with higher-frequency monitoring and precision.
Technical details from ISRO - https://www.isro.gov.in/Mission_GSLVF16_NISAR_Home.html
Do you have any sources or even hints of sources that I could search for to back up the claim that this has been done for a long time?
For example this: https://www.sciencedirect.com/science/article/abs/pii/S00344...
Search for 'land subsidence insar mexico'