Allardyce was sacked by Ashley after just six months in charge and was replaced by Kevin Keegan who has also left the club.
Big Sam told the Sun: “It is going from bad to horrendous now.
“There is a part of me that makes me think I’m glad I’m out of it. It is crystal clear now what the motives were for Mike Ashley.
“I think, in the end, he did buy the club in the hope he thought he could quickly sell it on for a vast profit.
“What I did wasn’t in the same line as him. I was in it for the long term.
“I was in it for a four-year contract and the building of a football club that over the years had declined.”
He added: “They finished 14th under Glenn Roeder, the year I took over, and when I left they were 11th.
“There was no danger of relegation — we were 12 or 13 points from the relegation zone.
“When I was there this time last year, we had the best start in 10 years and I think people lose sight of that.
“As a manager you always blame yourself first because you’re the one in charge.
“But in the six months I was there we worked tremendously hard and put a fantastic backroom staff in charge.
“Then we needed the players and the players just didn’t materialise because the money didn’t materialise to buy the sort of players the passionate fans demand so much.
“We only had a net spend of £9million. I thought Kevin Keegan was going to get that money but he never did.
“The continuous sales and players moving in and out over the summer obviously caused Kevin to conclude the job was untenable and the club was thrown into chaos.”