I was told that was the plan 10 years ago for Adelaide, in general, to focus on 'Tropical Asia' and Monarto 'Africa', that's why Sri Lankan leopards were in Adelaide's master plan as a replacement for their lions. However, the mention of the zoo losing its lions and giraffes created an uproar across Adelaide. Pandas, Tigers, Lions, Giraffes, and Orangutans are Adelaides major species losing 40% of those species would not be a good business decision. Adelaide apparently did research into this and found that there still remained a fair portion of their local visitors who rarely/don't visit Monarto. Thus losing lions and Giraffes would be catastrophic. Monarto is an hour's drive away from the city and for some people, that is too much (2 hour round trip). They also interestingly discovered in their research a new subset of Monarto's visitors who don't/no longer visit Adelaide. I assume these would be the more moderate AR types, who perceive Adelaide's lack of space to equal an abusive organization (without maybe realizing Monarto are part of the said organization).
ZoosSA had a great dilemma on its hands it had both the region's largest and smallest lion and giraffe exhibits so to any layman who has visited both zoos the comparison was bad. So for Adelaide, I assume it was either move their remnant lions and Giraffe to Monarto and suffer the loss in visitors or use the little space they had and expand into areas of the zoo once bookmarked for 'Asian' species. Thus this new 'mini' Africa was born.
Personally, I agree with you all on Adelaide moving their African megafauna to Monarto. From the sounds of it, the keepers at Adelaide do too, but they realize above all that it is a business decision.