Regarding the legal position, copyright is a complex issue and live shows in particular are a legal minefield because a) they rely on contacts and agreements made at the time which may or may not have been specified and if specified may be lost b) copyright law itself is fluid and so legal issues depend on when shows were recorded c) copyright laws have holes and grey areas.  All of which means none of us are able to tell whether or not the concert streams are legal; even those who know chapter and verse on copyright law don't have access to the necessary information (eg regarding the contract between King Biscuit and its recorded artists, or the artists and their recording label).

Seems to me we have no sound basis to contribute to this debate, so let's just enjoy the music.

Speaking of which, could you please stream the Genesis Philadelphia 1983 concert you have in your King Biscuit collection, full show please.  It's an incredible concert, band are in great form.  Thanks :)