I hope they don't. The big plus, as you've pointed out, is being able to use some great Minolta lenses.
But maybe the A3000 was testing out how a DSLR e-mount would be accepted?
I hope that was "the test" because it was a total failure and might convince them to keep A-mount alive! But it was a failure because it was such a low quality camera... A low quality E-mount put into the cheapest possible A-mount-like frame.
From Sony's perspective, the ability to use old Minolta lenses doesn't increase their bottom line.
There are 3 markets for advances cameras that Sony needs to target:
-- People upgrading from cell phones and P&S cameras. To these people, A-mount versus E-mount makes little difference. If they are buying lenses from scratch anyway.... And yes, A-mount can use old Minolta. But E-mount can use old Minolta.. old Canon.. old Nikon.. with the right adapter. And most of these upgraders are never going to go beyond 1-2 lenses anyway. Many of these buyers may prefer the E-mount over the A-mount as it has a more "P&S" type of feel. For those people who want a camera that looks and feels like a professional dSLR... those people are already inclined towards Canon/Nikon anyway. So for this market, Sony wouldn't have a huge amount to lose by dropping the A-mount.
-- Current Canon/Nikon/Pentax dSLR shooters -- already inclined to advanced cameras, getting them to add to their collection or change systems.
For this market -- The A-mount would have a couple of advantages -- If they really love their dSLR-like body, phase detect AF, etc.. --- Maybe the EVF of Sony A-mount might get a few of them to switch. But switching systems for an advanced user is expensive. That's a lot of money invested in lenses and accessories that now need to be re-sold. How many Canon/Nikon/Pentax users really switch to Sony A-mount and how often?
On the other hand, the E-mount is more likely to get them to switch -- If they have grown tired of their heavy equipment, the E-mount really offers an alternative. And with adapters, they can keep using their currently lenses. So for this market, there is far more reason to push the E-mount than the A-mount.
-- Current A-mount owners. For real entry level owners who only have a kit lens... doesn't really matter. These people could easily be convinced that Sony E-mount is simply a newer sleeker version of A-mount. Menus will be somewhat similar etc. But for advanced A-mount owners... They will want continuation of the A-mount.
Yes, some day the E-mount may have AF that can match the A-mount. And E-mount may have plenty of lenses available. But advanced A-mount users won't be happy with losing much of the value of their lens collections.
So are there enough current A-mount advanced users to keep Sony making the A-mount indefinitely?
If Nikon went with a mirrorless APS-C/FF cameras... I'm sure they would keep the same mount. Because there are so many advanced Nikon users who would want to preserve the full function of their equipment. Might make the camera a bit bulkier, but keeping the same mount would be more important than slimming down the camera as much as possible. But for Sony users.... where Sony never had more than 5-10% of the dSLR market... I just see Sony eventually "abandoning" the current users.