I do not think Steve Knightley has "failed".
I consider him to be a better-than-average songwriter and Phil Beer a jolly fine musician and producer.
Show Of Hands dull and samey arrangements leave me cold and I think they do as a band as little as they can get away with because they can.
They have an overgrown teenager, musically indiscriminating following but, additionally, have attracted attention from the far and nasty right who tried to incorporate the ideologically dodgy Roots.
If they wanted to they could very easily rise above this unfortunate fanbase, politically and musically.
madlizziecornish's now infamous claim that SoH are more important than Walter Pardon of whom she'd never heard is neatly annihilated in a Steve Knightley quote from an email to Ian Anderson which he has given permission to be used:

Ultimately this music is something we do but with Walter and his like it was what they were and it wouldn't be even be around for us to discover or re-create without his ilk!.

Which reflects where he stands currently in my estimation.