A consequence of breaking bail is that it greatly decreases your chances of being granted bail again since you've demonstrated you can't be trusted to keep your word and turn up for trial.
Since Assange was very lucky to be granted bail in the first place, on the rape charge, since he was a foreign national with no close UK ties facing serious charges, he's not going to be bailed again by an English court in a hurry. He's in exactly the same position as all those foreign-born radical Islamists, with far stronger ties to the UK than has Assange, who spent years on remand in the UK fighting extradition to the US and elsewhere, except that he was granted bail and abused it. Abu Hamza and Abu Qatada never got that chance, presumably because they weren't fashionable causes and didn't have wealthy friends with country houses who were prepared to accommodate them.