Other parks weren't coming from a space as poorly managed as Dreamworld had been prior to covid. The entire 4 years between TRRR and Covid were entirely botched, and the park had made some tough decisions to remove some core attractions as end of life with nothing in the wings to replace them (due to the ongoing botching).
I've heard both park operators speak about the symbiotic relationship the gold coast has - village and dreamworld rely on each other to support the industry and the tourism. The park returning to any semblance of profitable reporting after so long is a positive step for the coast and the industry as a whole.
Remember, Steel Taipan was a last minute opening. Mack had a cancellation, and an open build slot well advanced in the queue. What we've seen across the industry suggests that wait times for coasters have blown out, and with Dreamworld closing attractions everywhere, they needed something to act as an anchor. A reliable clone, a few modifications, they may not have had many options to do much more than that.
Sure, ST doesn't appear to have been the big draw card it could have been, but I wouldn't consider it a failed investment - it alone won't bring people to the park, but as time goes on, and as these other investments are built and open, it will bring balance to the park between basic and big thrill, and is future proofing the park against the loss of their only other full size full circuit coaster - gold coaster - when it eventually reaches end of life.