After buying the Series 5, as a first-time AW user who also doesn't use activity/health apps, I've become very interested to find all the apps I can choose from. Aside from tech publications showing "our top 20" style lists, and a limited showing on the AW App Store itself, there seems to be no large lists nor, seemingly, a whole lot of interest in the growth of the AW app ecosystem.
Am I missing something or is there only so much that the AW can do, and thus few apps on offer?
First, historically, Apple Watch development was difficult and very constrained. The framework had a lot of limitations and, on early watch models, third party apps were very slow compared to native apps (which themselves were not very speedy).[1]
This is changing now as the hardware gets better and Apple is opening up more powerful and easier APIs to third-party developers, but it will take a while for third party apps to catch up. And the situation is still not as good as it is on iOS.
The other reason is that there's a small number of app concepts that even make sense on the watch. The watch is very good at a few things: quick, glanceable interactions (like notifications) and fitness tracking. Apple suggests that apps should "support fast interactions and focus on the content that users care about most", and that "interactions with the Apple Watch are measured in seconds." [2]
A great deal of apps simply don't fit this category at all. Many existing iOS apps expose some basic watch functionality, but many won't, because it just doesn't make sense. Consider how willing you would be to hold your wrist up in front of you for 30+ seconds.
[1] https://marco.org/2018/02/26/watchkit-baby-apps [2] https://developer.apple.com/design/human-interface-guideline...
It will take another year or two, depending on how much effort Apple puts into improving the APIs.
The most recent episode of the Under The Radar podcast goes into this a bit: https://www.relay.fm/radar/174
Meanwhile the iPhone's sales are in the hundreds of millions, and more are sold per year than there are Apple Watches sold since launch.
So it's quite probable many developers don't see the need to make apps for the device. The market isn't large enough compared to other places they could be focusing their resources.
Outside of that, as people have said, Apple Watch development was difficult early on, there are fairly few concepts that make sense for apps on a watch compared to on a smartphone, and it's more challenging working within the constaints of a watch than a phone overall.
So it seems like more work for a more limited set of concepts on a device that may not have a market large enough to justify the effort.
I love the idea of devices like this but if it's something that requires you to look at, and manipulate things on, the screen... I'd rather just use my phone. I imagine many people buy them purely as a "hey look at me, I gots me an Apple watch!" and some people might buy them so they can glance at their watch (pretending no one notices) to check incoming text messages in environments where it would be rude or not allowed to pop out their phone, but from my own experience I just can't see them being practical enough to really have enough interest to spur development aside from "here's the most important data from our app mirrored on your wrist!"
Companies pulled out of AW because they found out that there is no reason for a watch-app. The screen is too small, feedback is limited by nature etc.