There are satellites in geostationary orbit that have realtime live feed and agile pointing capability. However, besides the SAR, RGB style observations are limited by clouds, and also you can’t switch out the sensors on a whim. Airborne platforms are always more flexible and cheaper for certain missions.
I think you are confused. Spy satellites do not use geostationary orbits.
Without leaking anything that's even remotely close to classified, WAMI (wide area multispectral imagery) sensor systems that can mount on even relatively medium sized group 3 UAV are really damn good these days. This is a pretty basic unit compared to the things that aren't publicly known:
https://www.logostech.net/products/redkite/
https://www.logostech.net/products/blackkite-i/