As others have already stated, by the time green is using the ‘infinite loop’ they have already won. By the time Blue has enough subterfuges or infiltrates to draw the foes entire deck they have already won. By that point its end game and Red can be busting out enough rites to level the world. By that point someone has already won and they are just toying with their foe waiting for the foe to concede.
There is no other card game with a ‘during your turn’ hand limit its usually ‘once your turn ends’ hand limit. While a hand limit probably would never even be reached, there is one major issue the fact that implementation would cause a bit of issues as there are some cards that would technically bypass this hand limit even if for just a moment (Ransack and Sibylline scrolls come to mind) so they would need to either implement a work around for those or make it so those don’t work when the hand limit is reached (which would make those cards useless at that point)
Plus you also have to take into account that you can easily cheese a hand limit by making sure your infinite loop never reaches 10 cards (which is how many coins you start with) or whatever the hand limit is. Its extremely easy to do this if you pay attention to your cards and your deck.
Honestly a hand limit wont really solve anything.