The SR-71 was retired because it wasn't needed, not with satellites that can read a license plate from orbit in real time.
The SR-71 was killed because of *budget cuts.
It's a wildly expensive plane to operate and needs a lot of fuel support to go anywhere and come back.
Satellite coverage isn't the panopticon you seem to think it is.
Yes they can read your license plate from space, but only if there's a satellite in the right spot, at the right angle.
Sometimes it's faster to put real eyes in the sky (SR-71 or *U-2) than it is to re-task an out of place satellite.
And despite the magic of satellite imagery, high resolution film from a plane still wins out.
*The military is currently looking at mothballing other types of fleets as a fallout of the sequester. Goodbye A-10 Thunderbolt.
**Yea, we're still using the U-2 spy plane since its introduction in 1957. The Pentagon plans to keep it in service until 2023. They're killing the drone program that was supposed to replace it.