Forced updating, is one major step toward the user fully losing control over their system. You are effectively giving Microsoft the right to do whatever they please, in the EULA. That is a gigantic loss of freedom over your operating system, all your software, and your entire investment, Microsoft could declare that all i686 software is unsupported, and at any time, remove the components that permit it to run, and you have no recourse.
Uh... not saying I entirely like the idea of the forced updates (I would prefer having a period of time to determine if I'm going to run into hardware conflicts and even though I'm going to be running Pro where it's possible to make that delay, it'd be nice in Home as well), but I think you're extrapolating a bit much out of this decision with your example of a potential future there.
Yes. Microsoft could theoretically do something like discontinue 32bit program and/or OS support and maybe that will happen eventually (most Windows 3.1 programs don't work in modern Windows OSes without tweaking after all and there is also Windows RT), but doing that at this point in time in their main operating system where there are still a lot of 32bit devices, hardware, and software is absolutely ridiculous. Even more ridiculous is the notion that Microsoft would force out an update on Windows 10 to purposely cripple billions of legit programs that ran just fine on it the day before just because the capability exists.
It's okay to be worried about the potential abuses that an update system like this could cause, but you also have to remember that Microsoft is a business and Windows 10 is being pushed as their next big main thing that's going to be spread across a variety of devices and hardware. They are not going to be trying to fuck their customers over in such a blatantly stupid manner. They might do things that are really disagreeable (Windows 8 and the start menu for example) and could break up existing workflow for some companies and users. They could potentially add restrictions a bit by taking certain paths in their design (or even this forced update philosophy). But such a drastic "fuck you" by completely destroying over half of their customers systems (including systems used for a lot of businesses) on purpose is not something they would do unless they are ready to kiss the company reputation goodbye.
And yes. I know you used Apple as an example of why Microsoft would be capable of being evil with their updates. But it goes back to your extrapolating here. Microsoft is not Apple. Microsoft is Microsoft. It's true that the capability exists (look at Skype for a better example since they did things like discontinue the extension api and the library that let other programs connect to Skype without having to use the Skype client and removed various other customizations), but Windows 10 is Microsoft's main baby at the moment. With how hard they are pushing this on multiple hardware specifications and trying to get people up-to-date, I highly doubt they are going to be going out of their way to purposely fuck people over in such a huge way. It doesn't make business sense at all. Also there's the whole thing where Apple iOS is distributed exclusively on Apple products made by Apple. Windows is being pushed onto a lot of devices that are not even remotely made by Microsoft. Big difference there as far as the operating system goals and what they are capable of getting away with there.
TL;DR: I can understand being worried about forced updates since there are ways that restrictions could be applied, but at the same time you have to remember that this is a multi-hardware OS and Microsoft is a company that wants to make money and it can't make money if it's bricking well over half of their users important company and personal software on purpose just because the ability to do so is there.
