For businesses, it would be the cost of doing business, but for me, as an individual using my computer to do volunteer work that I don't get paid for, it would make the difference of whether I could continue volunteering or not.
If they are making phones, making tablets, charging for licensing to Corporations, (don't know about OEM), making X-box, have an app store, and trying to push gaming into app installs only, plus they sell your info to vendors. Why would they need to charge anything for software or upgrades?
Apple you buy the OS once and can upgrade forever. And their OS is only $19.99 US, so I see absolutely no reason to charge anything for Windows 10, except maybe a nominal fee.
For those who think M$ wouldn't do this and it doesn't make sense, don't forget they want to charge you a subscription for solitaire. Does that make sense?
Charging for a game is one thing and for an entire OS upgrade is quite another thing. A game is an optional thing that one doesn't need to make the OS work and there are other games available for free. Charging for upgrades to 10 would be stupid on MS's part. I don't know what I would do if they did start to charge but switching to Mint would be a viable option for me.
But having said that.. it's just one file and there is no way to really say what it's for.
Keep calm and carry on..
This is really a non story - it is only about enterprise and people are just adding two and two making five, then re-engaging in discussion held a year ago. Just typical press conspiracy theory garbage.
You can upgrade from Pro to Enterprise or Education with a simple "change product key". Just like you can upgrade from Home to Pro with a key change. I just did an edition upgrade from Pro to Education on my desktop PC, completely offline, no internet connection. All the files were there for the upgrade. I didn't have to mount an ISO of supply any install media. The extra features are unlocked with the product code change. So it shouldn't be a big surprise if some Enterprise files etc are there in Pro, just in case they are needed.
My guess is they'll look to provide WaaS, and perhaps charge for "features" in the future.