what if a team having the ball but never taking a snap? the offense team keeps committing delay of the game or illegal formation etc... when they're pushed back to the goalline, the penalty will be half distance to the goal, but if they keep doing so, the game will never end?

Guess it'd be considered a forfeit. The commissioner has to declare it, tho.

It happens when a team refuses to play. In that event, the other team, if ready and willing to play, is the winner by a score of 2-0.

Unless there's a specific rule of which I'm not aware of...