the bigger names still get the oxygen of publicity (even if they've produced a duffer) where as whatever the "quality" of an independent release (from a lesser known name) it is still (much?) less likely to get the same.
I think that readers would expect to see a full review of album by the bigger names simply because they are the bigger names. If they are that popular then a poor opinion in a full review or dismissal to a short notice section in one magazine is not going to make a lot of difference to their sales.

I also guess that a thumbs up and a good review in the "and the rest section" is actually as good an endorsement as a fully independent release could expect from fRoots then.

Absolutely not! Full reviews in the current fRoots include the following:-
LUCY PRINGLE & CHRIS WRIGHT The Speaking Heart (Modegreen Music)
AILIE ROBERTSON Traditional Spirits (Lorimer)
HILARY JAMES English Sketches (Acoustics)
FRIBO Happy (Fribo Records)
CORDELIA'S DAD Double Live (Own Label)
MONSTER CEILIDH BAND (MCB Records)
THE FLK The Flk (FLK)
FAIRPORT CONVENTION Festival Bell (Matty Grooves)
BLAZIN' FIDDLES Thursday Night In The Caley (Own Label)

All these are the English language fully independent release or own labels and there are others in foreign tongues that are apparently a source of ridicule for some in this thread.