Even before the recent spate of services being shut-down, shortly after the Linux support was dropped, I moved Picasa to a kill list and started migrating what I was using it for to something else (Dropbox for storage and sharing).
I presume it's going to be killed, to me that's what the product state signals.
Snapseed is not doing any better, though. IIRC Google already shut down an app for Snapseed.
I think Picasa might wind up being merged totally into Google+, although by my established criteria that would not count as a shutdown.
Considering how important "usefulness" and "usability" are by now, maybe add a criteria along those lines - how large is the "your mom uses it and likes it" factor, how "contemporary" are the UIs, how much effort puts Google into polishing it (it does a lot with G+ and Gmail for example) - something like this.
Another criteria could be "level of integration" - how much can you use a Google product as a standalone project or how deeply connected is a product into another one (e.g. Picasa used outside of G+) - which might in the end indicate not a direct shutdown but a product's dissolution into another one.