First of all, thank you very much for posting this on Meta. We are, as you noted, at the beginning of our existance, and as such, we need to stretch; we must ask questions; it is imperative that we be open to asking questions. Are we headed the right direction? Are we being overly zealous about closing? Are we, as you suggested, scaring away valuable traffic?
I would like to note several things about the question referenced. I would remind you that the transient nature of this question was only one of the reasons for closure, and, in my opinion, not the strongest. However, let us address it quickly before flowing on to the other reasons.
1. Transient nature
As you said, every question and answer is to some extent of a transient nature; meaning that Google could put out a new version of their Google Home in which it is no longer possible to do something that is possible with the current version. However, these are not foreseeable changes, whereas we all know and expect that price and suppliers of a given product will definitely change.
Hence, the question referenced gives us answers which are expected to be short-lived, whereas the goal for questions on this site is that they would last indefinitely (not infinitely!).
2. Finding a particular product vs. updated product
While questions like these are fairly easy to answer, they generate a lot of content that needs very frequent update or removal. This is not the same as the Alexa question you referenced, which could always be applicable, provided you still have an older (the current) version of the Echo.
In other words, if I am asking how to do something with a Nest Thermostat, we can expect that the answers will be basically applicable indefinitely, even if they become applicable to a smaller and smaller audience as newer versions come out. However, when we move into the realm of sales prices and suppliers, questions become applicable for only a limited timeframe - and frequently only to a limited audience at that, since most places will not ship to all world-wide locations.
3. Buying advice
Buying advice is primarily opinion based. Okay, I know someone is going to say, "This doesn't have to be the case; it could be edited out." Then, I say, Edit it! The purpose of an on hold period is to give the community an opportunity to see that this question is in risk of closure and edit it up to status quo.
That being said, buying advice questions tend very strongly toward either opinion-based or too localized.
It is a fine line, I will freely admit. It's not an easy call to make. As you said, we need questions; we need askers. However, as a community, we have discussed this kind of question before, particularly in chat. And I have come to a conclusion which Stack Exchange has long supported: if a site cannot produce enough excellent material to keep it afloat, adding mediocre material won't help it stay afloat long term; it will just lower the standard of the site and actually chase away professionals, who begin to realise that their excellent questions and answers cannot compete with the mediocre material which Joe on the street can create by making a quick Google search and pasting in an opinion on "where to buy," etc.
All this having been said, I personally feel that this question is not very far from staying open. I would personally move for re-opening if someone took the time to spiff the question up a bit to give it a less transient nautre, also making it less opinion based and localized.