the decades long Reagan coalition.
To the extent there was a Reagan coalition it was dead by 1992. It was even starting to collapse in 1988.
Please prove otherwise.
Dukakis was ahead by double digits. Everyone expected Bush Sr's FBI investigation to tank him, but he won anyway. The same also happened in 1948. The reason the opposition parties lost is because in both instances, the parties presented hypothetical 'electable' candidates who they assumed would win, and so they attempted to run vacuous campaigns based on careful messaging. This is what the GOP tried to do this year (minus Trump).