One day Aperture will no longer work on a "current model" Mac. That's a given. What we don't know is when. Apple could do something on purpose to break compatibility and force users to import their libraries into Photos. Alternatively they can simply let bad circumstances for Aperture unfold in the name of progress for other apps. In that case Aperture may be crippled until one day it simply won't load.
It may be worthwhile to export every single photo in our libraries as 25-50% scaled JPG a files as a kind of contact sheet. If you see something you want to revisit then you can always retrieve the original image from the library manually. Open up the library in the Finder by right-clicking on it and click on Show Contents. You can either search by file name or drill down the directory structure if you can decipher it. From there you would have to import the image into your new processor and redo the edits. Who knows, you may end up with a better image on the second go-around because your skills have improved and the new software you are using is better.
Still, it's sad that Aperture is going away.
Years will pass before another program like it ever comes around.