This is why I highly dislike so called "cloud" applications. That being said, Flexi has 2 types of their "cloud" version of Flexi. One that they recently introduced is truly what most think of as a "cloud" app in that it is strictly renting your software. You stop paying, it stops working. We have Adobe licenses back to like version 7. If worse comes to worse and I need to open some old file we made in Illustrator 7, I can install Illustrator 7 and work with that file forever if I want to. You Adobe Creative Cloud customers..... what if you get out of the business and discontinue renting Adobe CC and down the road you want to open some Illustrator file? Tough luck.... Its a now useless file. Well - you can rename ai files to PDF and at least look at them with Acrobat reader but what about your In Design indd files?
On SAi, their perpetual license is different..... you pay once and you can run it as long as you like. In the perpetual license "cloud" is just some added features you do not even have to use if you don't want to. The only problem I see down the road with their perpetual licenses is if they eventually change things with the activation. They have 2 types of perpetual licenses, dongle, and electronic. Regardless of which you have both require activation, just the electronic license has to call home to maintain its activation status. If they ever go out of business or shut down the activation server you would never be able to reinstall and get it working again.
A bit over a year ago Adobe did the same with their older activation servers for CS2 versions of their software. They shut the activation servers down permanently. Many complained quite loudly so what Adobe did was to release a copy of their CS2 version programs with the activation no longer required. We can only hope SAi would do the same down the road if they were to change or disable the activation methods for older versions suddenly preventing users from being able to use or re-install their paid for perpetual licenses for older versions of Flexi. I sort of doubt it though....