Not entirely correct. The current situation on XBO is a bad one, meanwhile Sony's GNM solution seems to be working wonderfully for developers. As I pointed out, the developer for Metro Redux explains that even when using the Mono driver which is supposed to provide access to code "close to the metal" can be "a million times slower" (actual devs words) than when coding for GNM because of all the DX11 bookkeeping it does.
Also for your second point, we don't need to look any further than 360 vs PS3 where initial SDK for PS3 was a mess, whereas 360's was fine, this led to initial 360 games performing miles better than PS3 despite similar raw power. PS3's SDK having much more room to improve than 360 meant that there was a LOT more for the PS3 to gain despite 360 getting it's own refinements.
The hardware raw differences will always remain, however currently and according to developer feedback, the difference appears to be bigger than it should be, so you're seeing worse performance than what the raw difference should reflect. Ultimately the goal is to reach parity on the software efficiency level, but never parity based on the hardware difference, the PS4 always have the power advantage; I think that's where most people confuse what's being discussed, including believing the PS4 has equal ground to gain over the mess MS, just as Sony last gen, put out.