Non-subscription model pricing is an unsustainable dinosaur. In a world where literally everything is connected and interconnectibility is baked into everything, and bad actors have worldwide access to this interconnected network, it is simply unreasonable to expect a developer to charge a price once for software and then spend the rest of their life unpaid to keep it functional and secure, even as fewer and fewer users use the software.
Back when a program would install once to computers that weren't network connected, the buy-once software model made sense. We're decades past that point. Software maintenance is a never-ending and expensive endeavor. People who sell the buy-once software are selling you abandonware. They simply don't expect to support it as long as you want to use it. Once new customers stop buying sufficiently, they will move on. Yes, you can still use Office 2010. But it's not safe, and not comfortable, and by this point LibreOffice would be a much better choice.
Let's say you're a student, and you sign up for the yearly bundle subscription. You're getting more apps, always the latest version, with security updates, and it will be 7 YEARS before you pay more than the up-front cost of the old bundle?! If you figure that you can stick the unspent cash savings into a 4% online savings account (far from the best investment you can make), it will take 8 years before your cost is equal. I've used 8 year old software before, and it was uncomfortable to say the least. By that time, there were far better open source or reasonably-priced commercial options available.