Totally just based on my earlier 1% of 1% post. It's not an assertion of fact, it's example of scale, in my opinion, of how prominent I think the mentality of letting one or both of those specific features make 100% of the determining factor in a purchase decision. It might be a little bit of a straw man, but there are 4 different kinds of people that noticed whether or not the S6 has an SD card:
1. WOW THIS PHONE IS AWESOME!!! I wish it had an SD card
2. Wow, that would have been a good phone, but no SD card, no sale.
3. That phone sucked, wonder why it didn't have an SD card - if it did, it might have been better.
4. That phone sucked, even if it had an SD card, I wouldn't buy it.
Or something like that. My assumption (underline that) is that those 4 combined = about 3-4% of the people who considered buying an S6. I also assume that 50% or more of the people who bought an S6 don't know what an SD card is. I also assume that most bought the lowest internal memory device available because it's cheapest. And I also assume that most who bought it had a galaxy prior to the S6.
I also, also, also assume that I don't care what the real numbers are - if it is higher or lower, doesn't really bug me. The point is, that I am of the opinion that the number of people who know and/or care about the SD card are ridiculously small compared to the gargantuan number of people buying Galaxy phones. AC is one of the largest (and IMO is the best) locations for nerds to discuss and read about Android tech, and we have somewhere around 3-5% of the volume of regular users compared to those buying Samsung devices every quarter. If less than 10% of (guess) of AC users are inflamed by the presence or absence of an SD card, then that leads me to believe that at best half a percent of Samsung users are also that fervent about it.
But the numbers are illustrative, not statistics.