[someweirdperson]

>regardless of any outside factors

There is at least one relevant "outside" factor. While the connector is standardized, the housing end of the plug does not seem to be. As soon as a phone is in a case, the case's hole for the 3.5mm connector is too small to accept the housing of a normal 3.5mm plug. That's true even for the shell the active3 tab comes with, not only some cheap after-market. It still works with the connector not fully in, but not reliably.

Maybe my 3.5mm connectors are all too old and I should try to find a replacement with a more narrow housing. Or a 3.5mm male/female "adapter" with a narrow housing.

[zdragnar]

If you have a drill and a small bit, you can open up the external case's hole quite easily. It's an unfortunate task compared to the more universally sized options, but the trade-off is there if you want.

[grishka]

It indeed is something easily fixable. The one thing I dislike about wireless communication is that, besides relying on software that (hopefully correctly) implements scarily complex specifications, it uses invisible radio waves. For wired connections, you can see and touch the thing that connects your two devices. Thus they're much easier to troubleshoot.