Office has always been a subscription. They just made it obvious, as opposed to selling Office 4, Office 95, Office 97 with no indication that you were expected to buy the upgrade. https://en.wikipedia.org/wiki/History_of_Microsoft_Office for a long history of this if you care.
Most other software the same. With a subscription you can't keep and use the old version anymore, and you can't even keep using it if you stop paying (though there is often a free tier) with a subscription. However nothing has in practice changed except that they payment cycles are more predictable.
Most other software the same. With a subscription you can't keep and use the old version anymore, and you can't even keep using it if you stop paying (though there is often a free tier) with a subscription. However nothing has in practice changed except that they payment cycles are more predictable.