So, are you basically saying the expenses saved on designing the ride system would be allocated elsewhere in the ride's budget?
Not quite. For the sake of argument let's assume that an E Ticket costs 250 Mil to make. Any E Ticket.
Development of a new ride system would usually be an extra 10 Mil (such as something relatively simple like a rollercoaster with motorcycle like seats). For something very complex and new, that could be an extra 50-100 M for all of the R&D, testing, etc (such as putting a motion simulator on a complex/large dark ride base to create the first EMV).
So, a new ride like Pirates Shanghai would have originally cost the base cost for the E Ticket plus the R&D cost. So, 250+50-100=
300-350 Mil. A ride like Tron would have originally cost base E Ticket plus just regular ride system design. So, 250 + 10=
260Mil.
Cloning these attractions saves some money. Thats for certain. But they're still gonna cost that base 250. There wouldn't be tooooo significant a difference money wise between cloning Shanghai Pirates or doing a new ride with the same technology though as the 50-100 on R&D is already spent and not needed.
Overall, cloning can save some money, but it is not the huge amount people seem to think. Reusing already developed ride systems rather than creating brand new ones does save a lot of money though.
So, cloning Shanghai Pirates (or Flight of Passage or any other extra complex ride) would only be significantly cheaper compared to developing something new and insanely cool. Not compared to any regular kind of ride or reused ride system.
The reason clones are common is that they are safe bets and have already proven to be something people like. Saves the risk of opening something to an overwhelming chorus of "meh" like they did with Navi River Journey or Voyage to the Crystal Grotto.