Depends on what level of trust you need to have. Obviously you can’t even trust a multibillion-dollar public company like Google to keep maintaining a product forever, or even for a couple years.
On the other hand, someone selling a stable piece of desktop software doesn’t even require a tremendous amount of trust. Just the trust not to ship malware or massive security holes. Even if they fully retire and delete the source code, your software will keep working. That’s more than I can say for Google reader, or the Humane AI Pin.