It’s a great question, but I don’t think the article answers it.

Not in any academic sense, but in a real-world sense a software product is something that as a user you can rely on to solve a problem. Rely is doing the heavy lifting in that sentence.

You can rely on a vendor’s product if (a) they’re going to be around for a long time, otherwise the investment into adopting it isn’t worth it; (b) the vendor is committed to solving your problem in an ongoing way - meaning they understand enough of the domain (ideally more than you do) that they’re going to be a partner even as your own needs evolve; (c) they deliver the product in a dependable way - high uptime and security.

So it comes down to “can you depend on this software over time?”