Careful, Reagan did not win two landslides. His first margin was 9% but his vote total was only 50.4%, because independent 3rd party candidate John Anderson took about 7% of the vote. Anderson's voters were definitely not liberals but they were not conservative and definitely voted against the status quo (Carter) but also against Reagan.
Reagan's second win, definitely a landslide, did not necessarily win over these independents. His margin came from "Reagan democrats," basically blue collar voters who liked him personally even though they disagreed with his policies.
I think they liked his policies, Reagan's social conservatism and strong national defense positions, and his aggressive posture against the Soviet Union all over the world, and his patriotism and raw Americanism, really jazzed the blue collar voters.
Fixed it for you.
These Reagan democrats were just as pro life as Reagan and recognized that their party had abandoned the unborn. They were, however, liberal democrats but Reagan's personal likability allowed them to realize they had a lot in common with him. It was part of Reagan's big tent ideology -- you did not have to compromise your principles to get the people of the other party who agree with you to join you.
Reagan was right, but unfortunately, today the GOPe wants you believe that big tent means abandoning your beliefs to let everyone in, whether they agree with your principles or not. Reagan was not part of this big mushy middle.