> Every product relies on an external ecosystem for it to be useful.

I found a 6” adjustable wrench that was patented in the 1910’s. It was designed to pull square bolts off buggy wheels or something.

I use it all the time, but I’ve never seen a square bolt anywhere near the size it’s designed for.

I have all sorts of other well-designed products that don’t rely on complex ecosystems. Most are older than me, sadly.

It seems like it should be possible to build smart glasses that rely on, say, an Android phone which isn't going away any time soon.

Once an android phone stops receiving updates, its only a matter of time until google play services stops working on that version of android, and then it becomes a big PITA to do anything google related with it, as it keeps redirecting away from web pages you to apps that tell you that you can't use them. I wouldn't rely on Android to not go anywhere.

When your phone gets EOLed you buy a newer Android phone and the glasses would keep working.

If life was so simple.

The new Android version might have introduced features that render that old app worthless.

Examples of such changes.

Locking down use of private APIs (abused by some apps), locking down NDK to the official Android native APIs and public shared objects, both cases app gets killed when doing naughty stuff, sandboxed file system (now really enforced in upcoming 11), permissions (now enforced with the Play Store minimum target version), and a couple more.

So if the app happens not to be constantly updated, it might just be rendered worthless with a new Android phone.