"Once the novelty of an interchangeable lens compact has worn off"
An intentionally provocative statement*, I'd imagine and hope! Is it really the case that the big two are yet to commit to a largish-sensor CSC because their current formats are fundamentally better for being shackled by 35mm silver halide considerations, or because they are frankly sh*t scared about anything that might undercut and undermine their established ecosystems and the status quo? It's really no surprise that it's the companies with no substantial history in 35mm (or, in the case of Olympus, frankly nothing to lose) who are daring to be different, and truly innovative at present. There will always be a place for full-frame dSLRs for those for whom money is no object, but the consumer-level cropped frame EOSes and so on (mostly used more for cachet than technical merit, in fairness) are increasingly looking like bulky anachronisms.
* as this one might be interpreted, also, though spoken from the heart...