I'm not getting into any STN v LTN debate as quite frankly it's been done to death.
I assume Lee Baker Street's post is a response to my posting of FR's Winter schedule which was just a statement of fact, so seems somewhat unfounded
Indeed many airports, not just in the UK but in fact across the globe are becoming increasingly dominated by one or two carriers. It's partly down to consolidation in some markets but I think also because usually the dominate carrier helps drive up passenger numbers. That becomes increasingly important as airports increase their commercial activities and engage in greater competition with each other.
LTN and STN are both in a good position currently with a lot of growth and opportunity in the short/medium-term at least. Whilst the arrival of LS and one or two other carriers is reversing the trend to some degree, FR has driven the passenger growth at STN in recent years like no other airline would. We are seeing EZY and W6 becoming increasingly dominant at LTN for very similar reasons.
In terms of the hot topic at the moment of LCCs feeding into long-haul, it's the likes of EZYs LGW and FRs STN network that are likely to be attractive to long-haul operators and in turn could become less of a "hindrance" to those airports.