Landslides only happen with incumbent re-elections (Reagan, Nixon, LBJ, FDR). The trend in recent decades has been towards more modest re-elections (Clinton '96, Bush '04) and then actual declines (Obama '12) and now defeats for the incumbent party. No one can predict the future but I doubt that Trump's term will set up Vance for a commanding victory in 2028. Being the party in power is a net negative now, not just during midterms. Can't imagine what political environment would permit something like '64, '72, or '84 again.