There seems to be news, that since Anniversary Edition you cannot disable Cortana anymore.
Plus, I have to agree with hughw above, that there is a difference between phone and computer, what kind of data you have loaded on each. Windows 10, as it is currently, is simply unacceptable.
I disagree with the difference between phone and computer, for many people a smartphone or tablet is the only computer they own.
What's not opt-in, or even able to be disabled through any supported method, is web search through the taskbar/start menu search box. This means that search box keystrokes will be sent to Microsoft servers, though there are (opt-out) options for disabling or clearing storage of search history.
There is just too much money to be made in surveillance and targeted advertising, especially since margins are collapsing elsewhere and people want everything to be 'free.' Surveillance is the business model of the Internet, at least in the B2C space.
I'm not optimistic about it changing because frankly nobody cares. The only people who care are a small fraction of "cryppie" types and coincidentally these tend to also be the people who use FOSS and/or pirate everything. Not paying money is like not voting. Vendors have absolutely no incentive to give a damn about what you want. I am not aware of a single case where a product has been significantly harmed in the market or failed due to privacy invasion. In fact, even major security problems (also related to privacy) generally do not harm products in the long term.