Not belabor this too much, but...
I see where you are coming from as the OP just wanted Operating Environments and had to choose the most popular distros, but I disagree that the browser is the defining one no matter how important to do what you do. I use three browsers as a web developer and I hardly remember which one I am in, no matter what hardware I am on or what app I am running. I see hardly any benefit to calling the browser the OS and any difference currently as it is still just middleware and not modern hardware dependent. Some Distros are and can only run certain hardware and software. It is not helpful to say you just drive a GMC, but that it's a 2003 GMC Yukon 1500 with a V8 engine for whether you are getting it fixed, trading it in, or wondering if Sirius XM is available for it, or whether someone is just curious about your mode of transportation. Sorry to be blunt but it is a question of freedom and the more it is consolidated the less free you are as an end user. Apple is a perfect example of making up a chip for the iPhone 5 so that there is no comparison to other chips and other phones they'd rather you forget the specs and just see the beauty of the OE and the case of the phone (yet you wonder why it can't do certain things that Apple just refuses to allow). If only one browser is allowed and integrated into the OS, no choice. It is not just a technical reason. If you let GMC only allow you to put OEM tires on without choice, well you know where I am going. Less freedom, pay more, less competition, less choice for best of breed. I'm betting OP wanted to know Year and Model (Windows commonly defines that with the known versions of Windows), but did not care about what tires were on it no matter how important for it to run. BTW I love Debian base stuff, I want to try Arch Linux here soon, but currently just running Linux Mint (OS) with KDE (DE) using Firefox and Dolphin Browsers. Very helpful to define the individual pieces to it ...even to the average user.
I see where you are coming from as the OP just wanted Operating Environments and had to choose the most popular distros, but I disagree that the browser is the defining one no matter how important to do what you do. I use three browsers as a web developer and I hardly remember which one I am in, no matter what hardware I am on or what app I am running. I see hardly any benefit to calling the browser the OS and any difference currently as it is still just middleware and not modern hardware dependent. Some Distros are and can only run certain hardware and software. It is not helpful to say you just drive a GMC, but that it's a 2003 GMC Yukon 1500 with a V8 engine for whether you are getting it fixed, trading it in, or wondering if Sirius XM is available for it, or whether someone is just curious about your mode of transportation. Sorry to be blunt but it is a question of freedom and the more it is consolidated the less free you are as an end user. Apple is a perfect example of making up a chip for the iPhone 5 so that there is no comparison to other chips and other phones they'd rather you forget the specs and just see the beauty of the OE and the case of the phone (yet you wonder why it can't do certain things that Apple just refuses to allow). If only one browser is allowed and integrated into the OS, no choice. It is not just a technical reason. If you let GMC only allow you to put OEM tires on without choice, well you know where I am going. Less freedom, pay more, less competition, less choice for best of breed. I'm betting OP wanted to know Year and Model (Windows commonly defines that with the known versions of Windows), but did not care about what tires were on it no matter how important for it to run. BTW I love Debian base stuff, I want to try Arch Linux here soon, but currently just running Linux Mint (OS) with KDE (DE) using Firefox and Dolphin Browsers. Very helpful to define the individual pieces to it ...even to the average user.