Season Two, Three, Four, Five and Six Not Available on Amazon Prime Video?

One of the most frustrating things we find to show we love, go on line to see if there is a season to. Yet these are not available, nor ever become so on the streamer that showed season one. Prime video seems to be the worst about this. My assumption is there may be three reasons for this. Not enough iballs for the streamers, exectson beatncounters and unreasonable licensing costs or requirements on the part of the content owner.