The software industry seems to be heading towards subscription models, which have the advantage of allowing ongoing incremental upgrades rather than big 'point' upgrades. Of course, a subscription model ensures ongoing revenue for the software company, not least because your data is tied in to a product that you do not own.
You can buy 'point in time' lifetime editions of various Office components as well as Office suites, but they do not include the ongoing incremental upgrades - just security and some bug fixes. Adobe makes this explicit on those products they still sell lifetime licenses for: there is a continuous track for subscription customers that includes ongoing improvements and a classic track for lifetime licence customers that contains only security and bug fixes. Microsoft use the same approach but are less explicit about it: Word in Office 365 has improvements that Word 2016 bought with a lifetime licence does not.
I'm no fan of subscriptions; I'd rather own the software and know that my data is not beholden to a product that I do not own. However, the move the ongoing improvements in operating systems and the increasingly rapid deprecation of older operating systems means that you need application software that has been updated for the latest operating system version. After several years of holding out with Adobe, I've finally subscribed to Creative Cloud after moving to a new Windows 10 laptop last year. There are numerous issues with my old Creative Suite 6 Master Collection (which was the last lifetime licence version) on Windows 10 x64 and even those bits that can be made to work will not support the high DPI screen on my new laptop (which, in my view, is a huge improvement over a standard DPI screen). Subscribing to Creative Cloud has allowed me to stop purchasing upgrades for Acrobat as a separate product, and there are worthwhile improvements in Acrobat DC continuous as opposed to Acrobat DC classic (though, as Acrobat DC has just got a 2017 version number, there might be a new release of Acrobat DC classic coming - at an upgrade cost, of course). Creative Cloud includes Lightroom, which Creative Suite 6 did not.
I'm holding out on Office, not least because I own Office 2016 Professional, Visio 2016 Professional and Project 2016 Professional. I have a subscription to Office 365 through the university to which I am affiliated, though I am not currently using it and the subscription does not include Visio or Project. At some point I expect I will have to give in and subscribe to Office 365, especially as there is no discount for upgrading Office lifetime licences - you have to buy new versions at full price.