Newbie here, checking out demo.
Question: if Devonthink stops developing, and Mac OS evolution makes it impossible to open the final version, do I lose data?
Same if the database crashes.
thanks!
You won’t lose the content, you will lose the organization of the content.
Using the Finder, right-click on your database file and choose “Show package contents.” In the window that opens, you’ll see a folder named Files.noindex. This is all the contents of your database, organized in such a way that DT can use to access everything quickly. You’ll notice that it does not mirror the heirarchy that you may have created inside of DT itself.
But you can set DT up so that it allows you to keep files wherever they are in the finder heirarchy, too, though, right?
So if DV ever stops working (e.g. is not upgraded for a new Mac OS) I won’t necessarily be stuck with only a single window containing a vast heap of unorganized files…?
Adding files/folders to the database with indexing keeps them in their original locations.
But of course you don’t do OS updates before verifying software you rely on is compatible? 
And having a bootable copy of the previous OS on another volume (e.g. on a portable external drive) can be useful for running apps to at least export data if that’s ever necessary for any reason.
But of course you don’t stick forever at a given OS when a program you like ceases development?
I don’t, but know people who still boot OS 9 to run legacy apps that obviously are no longer developed.
Another scenario: OS development stops (e.g. Leopard being the last version of OS X for PPC systems) while app development continues (e.g. requiring Snow Leopard).
I was suggesting that primary data in DT databases needn’t be permanently held hostage if app development stops and becomes incompatible with newer OS versions. Sure, certain metadata is likely lost but that’s a risk I’m willing to live with.