The Broadcasting Act 1990 was the turning point. No, really.
Prior to that becoming law, Granada was essentially an unstoppable money-making machine. They had an effective monopoly on television advertising across Manchester, Liverpool and the rest of the North West; if the audience were watching TV and not the BBC they were consuming advertising sold by Granada in that region.
The arrangement by which they won and retained their franchise to do this was primarily awarded based on quality of service, and Granada had a reputation of delivering in that regard.
Such was the extremeness of their profitability that they were able to buy out multi-billion pound empires like Trusthouse Forte in the 80s. If you stopped for a meal on a journey, or stayed in a hotel (anywhere) there's a strong chance you would be paying Granada, indirectly. They were an unstoppable force. The only limit was that they were forbidden from expanding their media empire, at all, but that was equally protection for the company because none of their rivals could make a bid for them.
This is the backdrop to which Granada make a deep investment in Park Hall Leisure. It was intended as a way of buying expertise ready to build a studio-style theme park, but the opportunity presented by Britannia Park was too good to pass up and Granada were only too willing to build their empire further still.
The Broadcasting Act changed everything, in a stroke. All of a sudden, Granada was exposed - the regulator would now judge worthiness for the ITV North West franchise based on the amount of money they would pay. Not only that, but in the new world Granada would have to work harder to win the audience - satellite and cable stations were already nibbling away at their share of the audience, but so too now would Channel 4 as they sold their own adverts, and before too long Channel 5 too, not to mention the explosion in choice digital broadcasting could bring.
Granada TV couldn't be relied upon so heavily. The investments paused and the focus for the organisation shifted to retaining their franchise - which they eventually did. The long term investments, theme parks included, would be looked at again when funds allowed.
Perhaps the most critical change would be the weakening of the corporate protection Granada had enjoyed. The final bill did make it difficult for a foreign media organisation to takeover, but in theory Granada could takeover or be taken over by a domestic media interest, including any of the other Channel 3 (ITV) franchisees. Granada was able to use their still enormous market capitalisation to stave off a takeover, but their rivals were converging
left,
right and
centre and it was only going to be a matter of time before one of the companies would become big enough to devour Granada whole. London Weekend were lining up a purchase of the already merged and part-owned Yorkshire Tyne Tees, and the same again with Scottish. If these mergers went ahead, Granada would be in their crosshairs.
Granada got wind. It was kill or be killed, and they had no choice but to act. They paid an eye watering £0.8bn for London Weekend.
The company had gone from expanding rapidly in any direction it could with the TV business as the bottomless well, to contracting rapidly to protect the mothership.
By now it was 1997 and American Adventure had already been running on a much reduced budget for 8 years. Pearson was making waves with their investments at Alton Towers and BPB were at their height of their powers. In the grand scheme of things, the theme parks were now seen as a liability rather than a long term opportunity, and were dispensed of.
The new owners' plan A was to flip the park and put together expansion plans to make such a sale attractive. Six Flags and Grevin et Cie (Looping Group nowadays) were both interested. One can only speculate as to why this never amounted to anything but if I was to indulge I'd say it was because Derbyshire and Amber Valley councils made clear they would not support expansion. The park had always been a political footfall and in the time between Britannia Park's failure and the American Adventure's stalled development, the council had flipped from being supportive to being minded to stymie.
tl;dr - Momentum is everything and the Broadcasting Act had provided a pause significant enough completely destroy the American Adventure's.
I look forward to hearing this read out verbatim by Expedition Theme Park in 18 months time.