I wouldn't class Stobart in the same category as MSE/EU Jet. The SEN operation is/was much more modest and realistic for a start, not to mention SEN's better location and stronger catchment.
We don't have access to the financials, but pax wise DUB and RNS have done quite well and Groningen seems to tick along. Some routes not so well, but I would maintain the theory of a regional operation flying routes unsuited to large aircraft and therefore other London airports was sound. I do think though that they made some errors in route choices.
I don't want to open another can of worms over the other Irish routes but it is interesting to note that VLM are not achieving loads that are sunstantially higher than those achieved at SEN. Brand recognition shouldn't be much of an excuse because Aer Arann were small-fry at the London end.