Terrence O'Neil happened to be member for a Belfast constituency. As it happened the Bann Side was a very pro Paisley place. Therefore his personasl re-election looked close therefore he looked like he had lost the election.
In most places he would have beaten the wing nuts in 1969 by a landslide.
It might also have been different had the 1969 election been by STV. In the actual election several independent supporters of O'Neil won and in no case did an independent anti O'Neilist win, and I do not think many came close.
Oh and it might have helped for the moderate unionists to have offered the deputy Premiership to someone like Gerry Fitt.
This would have totally destroyed the ultra unionist movement and in turn it would have prevented the growth of the IRA.
It might also have helped if the unioinist inspired bombers of the spring of 1969 were arrested - a factor in O'Neil's resignation were bombings which were falsly blamed on the IRA