How many satellites do you have in orbit by chance? The idea I had in mind was that you would have many satellites in orbit, potentially with quality satellites as well (higher quality satellites scan faster and last longer).
Additionally, satellites do accrue an additional small delay for each chunk they've scanned - that is, the more used a satellite is, the slower it will scan (i.e. entropy and hardware degradation). Again the idea I had in mind was to incentivize regularly launching satellites.
That all said, I am completely open to suggestions on changes and/or additional settings to enable/disable the above, as well as to speed up scanning.
And lastly, the scanning cooldown setting should go all the way down to 0 if you really want to speed it up, though I don't recall how "balanced" it may be.