Assuming Griffin's $400k, I can see how Adelaide are outspending Brisbane (one decent import; Sobey took less than 36ers offer to move there) and NZ (didn't bring back their stud big, have Abercrombie at the tail of his career, and a few others likely to hang around NZ rather than chase money elsewhere). $400k is a decent $150k import and then 5x $50k to juice up other salaries - it's not small change even in the current NBL.
Might be wrong on specifics of when they signed/extended, but let's say Ramone, DJ, Drmic, Froling, Teys are more or less locked in coming into this season. Then you lose Sobey, Creek and Wiley, freeing up their respective salaries - that's not peanuts, right? Do you overpay for roleplayers (who might not move states and come here anyway) or throw money at someone you think at the time is going to fit your style and have the moves to dominate? Then you're tempted to spend again to upgrade for Randle. At that point, you're thinking you have two stud imports, a stud forward, a strong roleplaying import, Drmic and Froling capable of contributing. Only Randle has a certain style, Griffin plays one end, Froling regressed, etc.
What were you expecting DJ and Froling to be on?
Assumed they had locked in prior to the current arms race developing. Either they didn't, the race ramped up sooner, or they had solid steps up in multi-year contracts.