I think this was discussed on AVS over a year ago.
VC-1 was added to BD to buy Disney's exclusivity (after VC-1 beat the sh!t out of MPEG-2 in 2 officially run tests).
AVC was added at the same time to soften the blow (it didn't have FReXT yet).
HDi was developed by disney and Microsoft. Techgroup in BD recommended it. Microsoft was told it will be accepted if they join BDA.
Microsoft refused. BD overruled the techgroup conclusion and added BD+. Microsoft went HD DVD.
Lossless audio codecs are not mandatory most probably because licensing fees were not set for them
when HD/BD standards were written. Later they were priced at $0 if you have licensed the non-lossless codecs.
BTW, Gary Sullivan, who led the development of H.264 and got an award for it, works for Microsoft.
Gary Sullivan (engineer - Wikipedia, the free encyclopedia)
Diogen.