It's not actually a *high* landslide at 55%, the vote splitting just makes it seem higher. Something similar happened in OTL 1980, where Reagan barely won a majority of voters but still won a massive number of states.
But the perception is that reagan win with a huge lead afterall, what really matter is the electoral vote and he win big here . All over the news will be "Reagan win 552 EV" not "Reagan win 55% of the PV " (Which is still a big win in a political system where generally the winner win by 51% or 52% )