I think they are less popular because when people pick them those players don't win games.
I don't think Future is that bad, just it seems to be trying to do stuff that mostly isn't very relevant to the game.
Credit Card (Promise of Payment) just seems to not be a card anybody is ever really going to want to bring in. It's got a cool future theme, but I think it's just not a good card.
Glaxx is a silver bullet for a non-dominant strategy. Assimilate is potentially pretty good, but how good the card is depends on how bad the opponent is playing, it's very easy to play around.
When a lot of your board's cards are about stopping things opponents don't typically do, it's a fast way to a board never being used.
I have to point out here that I believe a 5 player game was recently won by a player using Future as one of their boards and, as I understand it, assimilate took a couple different cards that game. Having 5 opponents to take things from is a lot better than 1.
With Law, I think it's important to note that some of it's cards turn things off temporarily (Injunction) or potentially prevent you from doing things that you don't want to do anyway (Censorship Council, potentially).
If you stop people from doing things they don't care about you are likely to lose that game.
The same thing if you pay your resources just to stall the opponent and you can't use that window of time to get permanently ahead. Injunction may prevent them from attacking with Tech 2 units or something, but they are still there for next turn. While you are doing that, they can just cast heroes and level them up and kill you, too.
Control is about having the right answers at the right time and you can't just save up cards in hand like you might in other games. If you don't use it, you often can't save the effect for next turn.
I think Codex is just a game that's fundamentally hard to make control oriented game plans work in.
I want to point out that speed and tempo oriented game plans tend to be the bane of control decks in a lot of other games. Everything in Codex is about that sort of thing.