Four goals in five games for club and country have made their timidity look foolish, although the 52-year-old understood.
"They didn't want to risk it on the past (injury) record clearly," he told The Journal. "Based on what has happened over the last few games, £9m is a bargain. It was a bit of a risk a few weeks back."
When asked if he thought his rivals had erred, Allardyce responded: "Hindsight is a wonderful thing. If I had it I would be in Marbella with a massive villa and a golf course retired as a multi-millionaire."