There were a range of competing larger twin turboprops which came out in the 1980s-90s, most didn't succeed. There was a belief that because of seat-mile costs airlines would prefer them to jets. That hadn't happened with the Vanguard 30 years before and it wasn't going to happen now.
The thing that really killed it for all the turboprops was the development of the Embraer and Canadair regional jets, both from non-established manufacturers in the sector so that nobody took them seriously until it was too late. Even those who bought the turbos moved on quite quickly, and the ATP was particularly afflicted by this.
What this has to do with poor aspects of a type like the ATP is they see any future market going, and stop the product improvement that would have addressed a number of the issues.
It didn't help that the only three mainstream purchasers of the type were BA, British Midland (plus their offshoots of the time) and United, all of whom moved on from the turbo market. BA actually stayed with the type longer than some give credit for, from 1988 they lasted for 15 years or more.
BAe seem to have had a notably poor management of the programme, having built about 60 of them at Woodford they then moved production to Prestwick, from where just one was sold, the last one to fly was scrapped unsold, and a third abandoned part-completed. That really is a sign of management not having a clue. The ones with British World (mentioned above) and some others were effectively given away at residual sale price, having hung around as white-tails, the last of the Woodford production, for some years after production was abandoned. How you can decide to set up another production line when you can't sell your existing output just about sums it up.