Every planet is different so every probe needs to be different. Inner planets can use solar panels, outer plants did nuclear generator. Outer planets need large

Every planet is different so every probe needs to be different. Inner planets can use solar panels, outer plants did nuclear generator. Outer planets need larger radio dishes. Cameras for Venus are useless, what we really need are more landers. Mars is well photographed so more rovers makes sense. One reason that platforms aren't useful is that there aren't enough probes for economies of scale. My understanding is most of the cost is the space-rated components. NASA is starting to reuse instruments, the proposed Uranus probe will use ones from other missions.