Bad comparison - Hurler was a woody with it's own complications of rough track plus a park that hadn't seen a new coaster in 5+ years so RMC'ing it was a worthy option, Volcano was a prototype with a ride system that wasn't replicated anywhere so the expense to overhaul it may have been too much (my guess is they initially tried but then found it to be a money pit so scrapped it), and Tornado, besides being a water slide, had known incidences of injuries that couldn't be rectified with better maintenance procedures.
TTD, on the other hand, just needed someone to pay for the recommended hardware/bolts and should have been ok; KK is another version of the same ride model and Intamin had listed the model for sale making it likely they can relatively easily replace parts on it when needed.