Ha, I owned a moto droid and galaxy s1 and tinkered constantly, I honestly hoped android was past that.
I will spoil the ending of the movie for you:
Android will never be completely past that.
To get past that would require a more heavy-handed approach from Google, and less variability between devices (because variation means inefficiency). Maybe eventually some Nexus will give that to the nerdy crowd, but Android will never have an iOS ease of use for normals. And I hope it never does, because that means nerds like me will have the same problems on Android that we have on iOS (namely lack of device choice and an OS that assumes you are an idiot).
I'm glad my phone has acceptable battery life now, but I am still annoyed that I didn't get this phone at a discount (it's more expensive than my iphone 6) and I still have to supply my own tech support.
Look, I won't defend Samsung or their prices. After having a S2 and a S4 I got sick of them last year and switched to HTC for my primary device. The ONLY reason I got my wife a Note 4 is because I got a MASSIVE trade-in discount day one. I will NEVER pay full price for a non-Nexus Android phone ever again, heck I might never burn an upgrade for one every again. In this market iPhones simply have more value.
With that said, I don't think you are being completely fair. You are assuming that the difference between a perfect S6 and your S6 is better testing and software. Maybe your radios are going nuts finding a signal on your commute NOT because of some software issues that is some QC and a firmware update away from making you happy, but maybe the actual phone design doesn't allow for the same antenna strength compared to previous devices you are used to. So its not that the S6 wasn't tested enough, its that your iPhone was a high water mark for signal strength and Samsung's offerings are merely average (outside of the Notes) based on their hardware designs. Then it comes down to deciding if that is a dealbreaker for you.
Obviously many don't care about signal strength- the lower standard of Samsung is good enough. So to your family maybe it would have been good enough because its their first smartphone and they don't know better. You on the other hand had a recent iOS flagship to compare with. It is not making an excuse for Samsung to say the S6 can not be as good as the iPhone on that metric and still be good enough for most people. I also don't think I am making an excuse for the platform to point out that the Android phones known for their signal strength is Motorola.
The rub though is that if you get the Motorola for the signal strength you get in return a MUCH worse camera. So Android becomes an exercise in balancing your wants vs your needs. Pretty much like every Windows laptop out there. Heck most of us here expected so-so battery life out of the S6 because of a smaller battery than the S5. Read the thread, many threw the phone out of their consideration set for that reason.
As I said earlier, I wish we had that option in iOS. I wish I could get an iPhone 6 with a 1080p screen but worse battery life. Or that has 3GB of RAM in trade for a worse camera. iPhones have their flaws too, but because they are so consistent they don't become a problem because most heavy iOS users know to avoid running into those walls (maybe subconsciously). They don't load up 30 tabs in Safari like I do on my Android phone every day because somewhere deep down they know that the lack of RAM will make that experience a tab reload party. They instead begin to shift their habits to optimize on what Apple delivers (in my example being strict tab managers) which then over time makes it seem like everything "just works" because you never run into the stuff that doesn't work.
Can you ever get there with the S6? Should you keep it? I won't say yes to either. In fact I will say if you dislike it to get rid of it. Life is too short to fight a device that isn't worth fighting for. But I think it is folly to hold up iOS and iPhones as these high standards across the board, when really all it is is that Apple picked the poison for you instead of you doing it.