Adding my two cents to this discussion. I know this is a highly-requested feature and this has all been said before.
The problem is that for many games, particularly games with 4+players, it is very difficult to finish games even with the absolute slowest settings. 30 days, for a 4-player game, is generally not enough. Skull King and Terra Mystica are two games I love that are quite frustrating to run tournaments for, since they each have over 50 active turns per player. Feels like at least a third of the games I run in these tournaments fail to finish on time, despite being as slow as the website allows.
Right now, tournaments are tuned to work for short games. And on that front the system works well. Games like Can't Stop have thriving communities of hundreds of tournament players, sometimes multiple brackets firing every day. But for a game that has more than 40 turns/player (the majority of the Popular Top 100 list), good luck even trying! The only tournament players you'll typically get for longer games are people who are online 24/7, because having a life is not conducive to finishing a Terra Mystica game in under 7 days.

The "Can't be skipped" option has done wonders for this though. Now I can safely budget 30 days of my time towards a long game, knowing that *if* all the timing works out and every person takes at least 2 turns per day, we can probably make it. Still, a solid portion of games will not end on time, and the more relaxed clock does not do any favors for that aspect.
The user experience problem with tournaments right now (for long games) is that it adds palpable stress to your life knowing that every second you spend not online, you are inching closer to nullifying the result. Indeed, the moment your clock falls below 00:00 the game is out of your hands, and a losing player with more time than you can choose simply not to play. (This is the same issue no matter the "skipped" setting). Why would you subject yourself to that anxiety compared to a casual turn-based game? It feels bad. Only a small portion of people can sign up for tournaments in good conscience because of this.
Could we please have a single time-control that is longer than 30 days? Maybe it could be restricted to just games in the "long duration" category, or for tournaments with 4+ players, or just high elo, or just multiplayer elimination mode, if there are concerns about tournaments lasting for too long. There's plenty of players on BGA that log in every day to make their turn-based moves, but aren't comfortable signing up for the stress of attempting to finish a heavy game with 7 days of turn clock. A longer time control could revitalize the tournament scene for all sorts of titles on BGA. I understand the hesitancy to have games drag on forever and lose players by the wayside, but 30 days as the longest option is simply too short for most players and most games.