EasyJet need to wake up and smell the coffee. Even now they still see BA, AF/KL etc. as their main competition when in fact they should be far more worried about the likes of Ryanair, Vueling, Norwegian and even Jet2 to some extent here in the UK.
If EZY were serious about competing with FSCs (that requires high frequencies on core business routes) then closing such routes probably isn't the wisest move, and it certainly wasn't the wisest move to have closed both their bases at MAD and FCO in recent years.
Fact of the matter is, EZY constantly re-allocate their aircraft to where they believe will get the best returns - which usually seems to be somewhere with relatively little competition from other LCCs and/or in airports/markets where EZY is already well established (providing there is the capacity to do so).
By all means, it's a logical strategy however going forward you have other LCCs growing at a much faster rate than EZY and more importantly, in primary airports on EZY's territory. EZY have long benefited by being the only LCC with a significant network in primary airports alongside the FSCs. That is no longer the case and they now seem to react by reducing capacity and running away from their actual competition.
FR since around 2013/14 time have overtaken EZY by a vast extent in the likes of ATH, BRU, CPH, FCO, LIS, SOF not to mention also their foray into BFS, GLA, HAM, MXP, PRG to name a few where in many cases FR are well on course to overtake EZY. Already, FR have overtaken EZY in SXF which has long been one of EZY's largest bases. That's just FR, never mind VY, DY etc.