Agreed, it is basically the equivalent of not bothering to get your car serviced for five years and then being surprised when it breaks down and you have a repair bill as long as your arm that you cannot afford to pay. I hope they learn from this!
But they won't learn. If I neglect my car for 5 years then get a huge repair bill, it's me who is up the swanny / on the bus / push-bike. Towers neglect rides and just close them - the punters still pay admission, so no real skin off their noses as the vast majority will only visit once or twice a year anyway.
That said, it is pleasing what they are doing with Nemesis. Admittedly, given the made-to-measure shape of the terrain they didn't have a lot of choice without huge additional expense to put something different in.