With respect, you probably aren't talking to the developers. You are talking with sales and marketing types.
I mean, Umbran, I am I promise
actually aware of the titles and roles of people I interact with, and actually in most of what I do!

I'm not usually working with the sales/marketing people, because they're usually only needed when you're buying in something new or learning about a new product/feature or the like. With 3rd-party products (which is an awful lot of what we use) I work with a mixture of low-end tech people (not developers), managers, network/server people and actual devs, depending on the product, the size of the team, what we're asking for and so on.
It's definitely true that it varies a lot - the smaller the team and the newer the product, the more likely you are to end up talking to actual devs or their direct managers. One thing that might be worth noting is that very few of these products are "massive" in terms of userbase, and most are specialist/niche. We're talking businesses with low dozens to single-digit (or with one memorable but not appalling product, just one!) of employees actually involved with the product in most cases.
There is a persistent problem in software businesses of sales and marketing selling things before they are ready in either the technical or business senses. Yes, stuff gets talked about that turns out never to happen.
Oh for sure, what we've been seeing a lot is more stuff that seems to work, and then we adopt, and immediately find a ton of things wrong with it that the providers were unaware of. Then they spend six months slowly fixing the issues whilst we can't use it until they do.
I gotta say this for the main products we work with though, if they say specifically that they're going to do something, like actually put it into the "Q2 X will happen" sort of plan, it's almost never more than a quarter later, and it does pretty much always happen. It's the stuff that the announce in more of an un-dated, "We're planning to do this cool thing" way that you have just not count on at all.
And very frequently, they try to manage expectations, saying things like, "We plan to do X," but the customer usually takes that as a commitment anyway, so, I kind of have to shrug and move on.
Of course. None of us are morons though - we don't take "plan to do X" as anything at all but a fanciful notion that would be lovely it happened. When something is pinned down as coming in version 9.2 or whatever, then it's worth planning for. Even then caution tends to be warranted because so many companies ship half-baked features.