There is no useful evidence to support the claim that a6000 is outselling the D3300 either...
The only evidence you gave was Flickr, which is flawed, and
Amazon, which it's under the D3300 on that list.
One reason I'd be reluctant to advise someone who is thinking of picking up the hobby of photography from buying Sony mirrorless is there is no room to grow.
If you want to move to full frame, or if you want to get that 70-200mm f/2.8 lens, or that ultra-wide 10-18mm, there is less choice there, in some cases no options.
When Sony's lens lineup gets better, I would give them another look for sure.
No, we don't know with any certainty. I'm just disproving the statement that the D3300 vastly outsells the A6000.
But what do you mean there is no reason to grow? I'd actually say the exact opposite with the Sony system. Again, I'm currently a Nikon shooter. I have no horse in this race.
But to me, by being a Nikon or Canon shooter, I'm limiting my growth to whatever that system gives me.
On the other hand, Sony is going in the direction of unlimited growth potential. Moving in a direction where I can affordably step up to full frame. Moving in a direction of allowing me to use ANY lens, from ANY system. As a Canon shooter, you can only use Canon-mount 70-200/2.8 lenses. A Sony shooter can use the Canon-mount 70-200 lenses, the Sony A-mount 70-200 lenses, and likely very soon, the Nikon mount 70-200/2.8 lenses. So far far more options for the Sony shooter, but much of that is in the future. And for a Canon shooter, if they want to grow into full frame, they need to change all their lenses anyway!
My advice is simple --- If you are already invested in a system, there probably is no reason to switch. Think twice, before going through the trouble of switching. Your current system can probably meet your needs.
If you are not invested into a system -- Then think carefully about your short-term and long-term needs. If you have highly specific short term needs, then you need to carefully weigh each system. There may be a single lens that becomes the deal-maker/breaker for you. There may be a single feature that becomes the deal maker/breaker for you.
If you plan on only doing "kit" type APS-C shooting for the foreseeable future, unless you just love big bulky camera bodies, it is very very hard to recommend traditional dSLRs to most people. Take a Rebel or D3300 with kit lens and basic telephoto kit lens... and it's hard to see any advantages over a Sony A6000/Fuji/Samsung. Sure, you can say, "hey... maybe in 5 years they will want a light-weight 300mm prime, so they really should go with Nikon, but not Canon! Or maybe in 5 years, they will want a 11-24 ultrawide, in which case they better go with Canon, and not Nikon!" Obviously, most novice shooters will never go beyond kit lenses, maybe basic primes. And for those that will eventually get advanced lenses, they don't know which ones they would want yet. They very well might want a 135STF lens, which is only available in Sony mount. And 5 years from now, those Sony cameras will be full universal mounts anyway. Probably in the successor to the A6000.
I have a simple dare for you... Go rent an A6000 and try it for a week. Get over hating it in the first couple of hours as you get over your prejudices... See how you feel after shooting with it exclusively for a few days. Then comment objectively.
It's easy for all of us to say, "I love my current system... I'm sure it must be better than other systems.. though I really have no experience with those other systems... but mine must be better."
I always find the most objective discussions are when people discuss the negatives of their current system and positives of other systems. (I am formerly a Sony A-mount shooter, I am current a Nikon F-mount shooter.. I have never ever been a Sony mirrorless shooter though I am very familiar with the product).
So try it.. In fact, I dare both of us... If you will go try an A6000 for a week, I'll try the camera of your choice for a week. And then we can compare.