A rather long post...
I generally have weak hardware. I like silence (read fanless) and Windows 10 uses more resources than any version before it. It's heavy (try using it on a HDD ) without providing anything I want that I can't get in Windows 7 or 8.1. Then there are the privacy and forced update aspects which made it a non-starter for me. I have even stopped testing it, because I don't see the point. I'm still optimistic though. Many users are concerned and according to Netmarketshare (website statistics) Windows 10 has around 28 % desktop share, while Windows 7 has around 48 % (August, 2017). Right now Windows 10 is growing at a very slow pace, but that may change of course.
What I'm trying to say is that if MS doesn't want to lose a good chunk of their userbase, the company has to make some modifications to Windows 10. At least give users control over updates. Giving home users access to a stable (5 or 10 year supported build) would also go a long way. Wouldn't it be great if all Windows 10 users were on the same build, except Insider users? It would be easier for developers too.
Desktop Linux is getting locked down
While Linux potentially could provide a new home for disgruntled Windows 10 users I wonder if that will be the case. There is so much stupidity going on in desktop Linux land. All in the name of "security" and "security" in this case means locking down the system and removing the user from the equation. Taking away maybe the most important reason some people like desktop Linux.
Being free to poke around and tweak the system just by editing simple textfiles. "Linux is not Unix" as they say, but I like the Unix way: Everything is a textfile written in human readable text. No registry, just edit textfiles to tweak your system or use a GUI program to do it for you. This was always the core strength of Unix (Linux). Take that simplicity away and the power of Unix goes away.
MS has the resources to write complicated code. Linux devs don't. When they write complicated stuff like Systemd it works like shit. Unfortunately many distros have adopted it and some people defend it for reasons that don't make sense to me. For me, Systemd is for Linux what Windows 10 is for Windows. And it doesn't stop there. "They" want to kill most of the customization too with Wayland display protocol. Maybe Wayland makes sense on a phone, but not if you want cool stuff.
One might think that this doesn't matter for ordinary people, but it does. If you want to get away from Windows 10 for whatever reason and you are willing to accept less hardware and software support, then at least you want a stable system. There is no guarantee for that anymore. There never was a guarantee, but 5-10 years ago desktop Linux was simpler and saner (from a Unix perspective). Everything has been rewritten the last ten years and only the kernel itself (Linux) is "production quality". Everything else is "developer playground". A bit like Windows 10 actually, only difference MS has more resources and can afford "experimenting".
I don't think disgruntled Windows 10 users will go to desktop Linux in meaningful numbers. They will stay on previous versions (which we already have seen by the numbers from Netmarketshare) or use phones and tablets more. Apple could expand their userbase if they wanted, but they don't want to. It's more important to keep Mac prices high. Chromebooks could also grow a little especially with Android app support.
I have seen on various forums that the resistance to Windows 10 is pretty compact (or at least vocal). I'm confident Windows 10 won't reach 1 billion users before 2020. By users I mean real users and not "Monthly Active Users" who fire up their Windows 10 VM once a month. I have no desire to see Windows 10 "fail" other than it may be the only way to make MS listen to users and give back some control. A PC should be a personal computer, not a thin client experience.
Unfortunately, there is only one way to combat what I consider "bad ideas" - don't adopt them. If I don't like Windows 10 - don't use it. If I don't like Systemd - don't use it. If I think Apple prices are too high - never buy anything from the company.
If you like Windows 10, personal assistants, virtual reality, augmented reality, voice recognition and mobile-focused tech; be happy because the future belongs to you. My problem is that nothing of this excites me. I complain about the “smartphone fetish” that has affected most of humanity, but maybe I’m just jealous of people who have something to be excited about. If I would be excited about the next build of Windows 10 or the next iPhone then my life would be, well, more exciting.
and one laptop that can't do any better than 7. I'm thinking of putting MX 16 Linux on it.
That would be the distro I would pick for older hardware. Most modern distros contain Systemd, which I'm not exactly thrilled about, but MX Linux works around it. Stable and lightweight - not that common in Linuxland anymore - enjoy it while it lasts. Probably half the RAM usage of Windows 7 if you uncheck a few unnecessary start-up apps. Typically around 350 MB. If you are a Nvidia guy and install proprietary Nvidia drivers that number will increase.