Ageing and unsupported
I wonder how much it would have cost to train a new team to support the ageing systems?
Then run them for, say, 3 years whilst the new teams collaborated on documenting functions and requirements?
Possibly less than paying someone to replace the systems when apparently nobody had a clear idea of what they were replacing and so couldn't cost the time and effort.
I assume that the old systems are still running anyway, and likely to be doing so for some considerable time yet.
Then again the supplier (not clear if Oracle is just the platform or is also the developer) may have just bid a figure it knew would be acceptable with no idea of the actual cost.