Sony's big 'problem' with lenses is that every user group from every other platform under the sun knows what they should do, and all of us have no reluctance in telling Sony what we think - down to full specifications, weight, size and flavor. Sony very likely know their market very well and set priorities accordingly. After all, they developed the a7 system in the first place, and the above simply indicates how much more appealing these cameras are than what the opposition is offering.
What has Canon or Nikon done lately that is not just another 1-2% on top of what they had already? They just seem to make the same camera and stick a new number on the front of it. They are victims of their own market success, and cannot make any serious changes to their cameras for fear of upsetting the base, which seems made up of the most conservative people, rather intent on keeping the future at bay. Sony are very clear that they welcome competition, they know it is the essence of capitalism. Competition improves the breed. C/N are stuck in an evolutionary cul-de-sac.
Ask yourself this: what would the camera market look like without Sony? No sensors for Nikon, no D800/D600, no FF mirrorless, no NEX, no RX series, no RX1, the mirrorless segment still dominated by small sensors in small expensive and quaint attractive bling bodies. Leica M users still complaining about the pricy M bodies. In terms of innovation, market impact and resourcefulness, Sony owns the past 2-3 years.
Full frame would still equal very large, heavy, complex and expensive DSLRs with lens ranges that are as out of date as they are extensive. Made by companies making that exact same thing for the past 40 years. No thanks, I'll take the present situation over that dystopia.