This is coming from the perspective of someone who owns both the SLT a77 and the a7. I do not foresee abandoning the A series lens mount as I find the new camera mounts to serve different tasks. For my general, scenic photography, I carry the a7. It is admittedly expensive; however, the kit lens a 28 to 70 mm film is a good general purpose lens that is used for scenic photography. On occasion, I like to use an extreme wide angle lens, in this case, a 20 mm Nikon f2.8 with an adapter. Although this lens lacks autofocus and stabilization, such features are not as important with this focal length than they are with the longer focal length normal and telephoto lenses. It amazes me how much can be accomplished with these two lenses. Good quality prime legacy lenses can be very affordable.
Recently, I have bought the 70 to 400 mm Sony zoom lens and that is permanently mounted on the a77. This lens is for animal photography and I love the speed with which it focuses (I managed to get the older, discontinued version at a good price from BH photo video). It matches up nicely with the a77 and this lens really needs fast focusing and image stabilization. I have managed to photograph handheld, at its full focal length of 400 mm. This amazed me as the pictures were quite sharp and the results very satisfactory. Although I have the LA-EA4 adapter and can use this lens on the a7; however, I do not. With such a long lens, its weight exceeds that of the camera body and I find no benefit to using it on the a7.
So my answer is, do not consolidate if you have a wide-ranging interests in photography as you will find benefits in using either the a series of the series lenses. If you want a portable outfit, then by all means go for the a7; however, while its light weight is attractive, it becomes much less important if you use a long telephoto. The weight of the lens will be much greater than the weight of the camera body.