No Bush performed solidly in TX. Reagan’s margins are completely irrelevant here because he nearly won a coast-to-coast landslide, whereas W won a squeaker in 2000 and a close race in 2004. Just look at TX’s margins before and after he was President and you’ll see that in 2000 & 2004 he got one of the biggest home state bumps in recent memory. This home state effect turned TX from a Likely R state into essentially a titanium R state on both the local and federal levels until the rise of Donald Trump.
1988: R+12.6
1992: R+3.4
1996: R+4.9
2000: R+21.3
2004: R+22.9
2008: R+11.8
2012: R+15.8
2016: R+9
And before 1994 Texas was just a Lean R state at best and at state level was a Lean D state and Bush basically obliterated the Texas Democratic Party for a generation . I mean Democrats have won state wide in Wyoming , Utah , Idaho , Oklahoma more recently than they have in Texas and that is all due to George W Bush .