I think launching stuff with nuclear RTGs would probably be met with red tape :(. Even if they are basically impossible to destroy even with a failed launch. I'm sure it will happen again but sadly not as fast or as often as I wish we would.
Uhhh lots of stuff is launched with RTGs still. Curiosity is powered by an RTG.
Almost everything uses RTGs now if it's going to be far from the sun (like past mars).
Ahhh I heard there was controversy for some launches. I'm very glad I'm wrong, I think RTGs are so awesome and the closest we have to sci Fi energy generation in space.