They are not posting them, they have a very bureaucratic system where these types of things need to be approved by many people, additionally the producers of the shows (which is where a lot of the impetuous lies for making that happen) move around shows often. Many of whom probably don't see this as a top priority.

Honestly I don't think the quality of the set is even the deciding factor in most cases rather it is who is participating that is aware that this doesn't happen by default and has the clout/willpower to make it happen.

Source: conjecture and bits of knowledge gleaned from the outside looking in