Cards with the mobius strip (infinity symbol) in the title can break the 3 per deck limit, right?

no. That symbol is shorthand for the ability to return from the dead or discard pile They are still limited to 3x in a deck.

Most cards when they are taken out of play and placed into the discard or the dead pile are considered to have lost their texts (even ones in the house deck)? Well, except the ones with the Möbius strip, right (whose abilities allow them to be activated even in the discard/dead pile should the conditions meet)?

The so called Mobius strip is just a reminder/memory hook that the card has a game text which can be activated from the dead and/or dicard pile. The ability to be activated from an out of play state is granted by the card text, which must specifically allow the out-of -play action.

Ruvion said:

As Old Ben implies, strictly speaking no card loses it's text when out of play. It's just that game rules say that no card is actionable when it is not in play unless specifically said so. So the "infinity" symbol is not NEEDED in order to allow card text to be active from the dead/discard pile. There are cards that can be triggered from such areas that do not have the symbol.

The symbol itself has no meaning in the game. It's essentially an aesthetic device on the card to help remind you that its text specifies use from the dead/discard pile, but it does not actually indicate or enable that use.

A simple visual reminder...got it.

yeah its supposed to help you remember to trigger it, but people still forget all the time...just ask the Joust champ

Or you could 'cheat' like the joust runner-up and place cards like that on top of your draw deck to remind you, and still forget