You now see where the revenue stream is
Google and Apple make money on tablets and smartphones by the app store. Microsoft wants to do that too. This is the purpose of Windows 10. Consider.
Programs are now called apps. Why? Because people are used to buying apps through an app store. People start calling programs apps which means they should buy them through an app store. Have you noticed that Windows 8 and 10 put the store icon back on the taskbar after every update? (I don't have Windows 10 and never will. But I do help a several unhappy people with their Windows 10, for a fee of course.)
I've already seen Windows 10 block legitimate programs because it flagged it as a security risk. This program that was flagged was a driver from HP's website. There was no instructions on how to override the security flag. I had to Google it to discover the only way around the false flag was to use a command prompt as an administrator. Flagging a program as a security risk is fine, but you must give us clear and easy to follow instructions on how to override the flag. But think about this: what is to prevent Microsoft from blocking all programs that are not installed using their store? Or worse, block competition. Or worse still, require payment for a security certificate before the program can be installed. All for your protection, of course.
"Sorry, Office 2003 is blocked because it is a security risk. Install Office 2016 instead! Better yet, Office 365." "Sorry, Classic Shell is blocked because it is a security risk." "Sorry, Firefox is blocked because it is a security risk. Use Edge instead!" "Dear VLC: that is a nice app you got there. Sure would be a shame if it didn't work on Windows anymore. Don't worry, for a small yearly fee we will make sure people can still install it on Windows."
Apple has a walled garden for their iOS. What will prevent Microsoft from having one too?
Herd everyone on to Windows 10 by as much force as you can get by with. Force everyone to use the Windows store. Profit. It won't happen overnight. Shakespeare said "And many strokes, though with a little axe, hew down and fell the hardest-timbered oak." A little bit here, a little bit there and people won't revolt at not being able to do what they could do. The only question is, will businesses stand for it? Microsoft loses the businesses, they lose everything. Employees will start demanding the computers they use at work, and if Microsoft pissed off businesses enough it won't be Windows machines. The people Microsoft needs to keep happy are the ones they are angering, as evidenced by forcing the Windows store on computers, like it or not.