If Mojang wants to prevent people from using resource pack templates, then they have a responsibility to either arrange the game assets in a way that doesn't make templates a necessity or to provide a template themselves so that others don't have to fill that need in their stead."
Let me ask you this, How do you thik the thousandsupon thousands upon thousands of people making packs get their 'templates' from?
Mojang ALREADY has given us means to make OUR OWN TEMPLATE. By opening the .jar and extracting the ASSETS folder, BAM you are DONE! That is also FAR easier then it use to be before when we had terrain.png and several folders we needed to make sure we grabbed. Now it's one folder, easy as that. This is done legaly for your own use as you already bought the game to get the .jar. You are taking their assets and using them for your own edits. You paid to gain access to their resources.
But theres a line between using default textures as a template for your own and only passing around your own work, VS editing a few texture's then passing out the rest of the default textures with it. Worse, sticking such behind a pay link, so you're selling stuff included with your few edits that don't belong to you.
That is what Mojang wants stopped, and they are doing so by making it illegal to pass around their default assets and with this new pack format. This way you can use their work as your own personal TEMPLATE and just delete the stuff you haven't edited to then share with others.
As I pointed out before, the assets in the jar file are not organized using the same file hierarchy that is required for resource packs, and many of the required files are absent entirely.
I'm somewhat surprised that you didn't already know that. But then, I see that you've never made a resource pack, so really, why should I expect you to have known that?
You want to know where thousands upon thousands of people making packs get their templates from? We don't. Because there aren't any. Instead we have to do hours if not days of painstaking research just to find out what the correct file names and locations for the various resources are supposed to be and how to format the various scripts, using almost entirely unofficial sources with incomplete information because no official guide has been provided, and then pray like hell that Mojang doesn't decide to change all the file names without warning for no apparent reason... again.
Let me give you an example.
I just finished laboriously adding line-breaks to the latest version of the en_US.lang to make it legible and therefore editable, which took up large portions of the last two days. And do you know what I discovered? Despite being pulled from the .jar after updating to 1.8, it doesn't contain entries for any of the features added in the 1.8 update. It doesn't even include entries for horses, which actually were present in previous versions of the file.
Since I can't use a template and I can't use the en_US.lang itself as a guide, I have no way of determine the proper format for the .lang entries for this features.