Why was he re-elected by a wide margin?
Here's government revenue in the BR era (Before Reagan):
FY 1977 $356 billion
FY 1978 $399 billion
FY 1979 $463 billion
FY 1980 $517 billion
Here's the wonderful DR era (During Reagan):
FY 1981 $599 billion
FY 1982 $618 billion
FY 1983 $601 billion
FY 1984 $666 billion
FY 1985 $734 billion
FY 1986 $769 billion
FY 1987 $854 billion
FY 1988 $909 billion
Conclusion: Government revenue increased bigly under Reagan even while Reagan was mostly getting government out of our way.
Source: https://www.thebalancemoney.com/current-u-s-federal-government-tax-revenue-3305762
The real question is: Did Actual President Trump tie his 49-state landslide or beat it?