thurrott[.]com/windows/windows-10/197699/windows-7-enters-its-final-year-of-support
neowin[.]net/news/windows-7-extended-support-ends-one-year-from-today
I imagine speculation on what happens then, in a year, will be all over the place, but personally I tend to feel it'll be pretty much a non-event. I think that the majority of businesses don't have the resources in place to upgrade Windows on their current hardware. Microsoft extended XP's support, but under Nadella they don't seem to even like Windows that much, so who knows. The chief issue for Microsoft may be more along the lines of not wanting to allocate warm bodies to work on win7 patches -- judging from the rollout of the last 2 versions, they don't want to put the necessary number of people to work on their current OS, Windows 10. It would be logical to think that the reason they gave away the upgrade from 7 to 10, was so that they wouldn't need to work on win7 any longer than absolutely necessary.
And I'm really not sure that having or not having the latest security fixes matters a whole lot to many of those people & businesses still running win7 anyway. The reason win10 makes it so hard to avoid updates, is supposedly because so very many never install the patches that come out now twice a month for Windows 7. If you're not installing the hotfixes now, why would not having any hotfixes in the future matter?
I don't think that the experiences from XP's end of life really apply. I think the numbers of people using XP declined because 1) win7 has more features, 2) the architecture was different enough that new software worked on win7, but often wouldn't on XP, & 3) more software became available only in 64 bit versions, while in XP 32 bit was the norm. Looking at win7 vs. win10, only the part about new features applies, and for many, those new features aren't something they care about or want.
That all said, all hardware eventually dies. Some of it will be replaced. Many will not want to perform the extra work needed to get win7 working on most new hardware, e.g. Microsoft doesn't provide USB drivers for current hardware & the old versions won't work. And Microsoft might make it harder to add already existing updates to a newly installed copy of win7, like it periodically does with XP [updates for the "embedded" version are still provided monthly]. So while win7 might seem like it's never going away, eventually it should become pretty rare.