I tried to quickly find a map online showing soil types in Europe and the Middle East and failed. However, if you are willing to take my word for it, continental Europe had much more agricultural potential than either the Middle East or the Mediterranean (Greece/ southern Italy/ Spain/ North Africa). Continental Europe had heavier soils that required some additional tech to exploit. But of the areas in the Mediterranean and Middle East that had developed city based civilizations as of the time of Alexander the Great, only Egypt due to the Nile could match the agricultural potential of continental Europe. And before the industrial revolution, agricultural potential was decisive.
So whoever gets to continental Europe first wins, and that could even be the Po Valley, which the Romans conquered between the first and second Punic Wars. Better agricultural potential means more manpower. That means either some civilization develops in northwestern or central Europe (but remember the heavy soils), or a Med based civilization gets there, probably from Italy though possibly from Spain.
Rome is really well placed for this, but in a situation where Rome doesn't get off the ground, then it will likely be one of the (other) Etruscan cities. As other commentators have pointed out, the only other candidate is Carthage, in a situation where Carthage dominates Italy and Spain. And this could happen. Maybe a situation where Macedonia or Epirus expands into the western Mediterranean for some reason.
But its going to be an empire founded in the west and moving east. It might not get as far east as the Romans got, or it could get further, but that will be the dynamic.