This does accomplish a couple points though. It shows the people in that sport that the sponsor cares enough about the sport to be seen. It also often means that the sponsored parties give feedback to the company about the product they are using to make it even better.
Apple does neither of those things and it shows, sometimes quite badly.
Apple certainly spends plenty of money on advertising. When Apple wants to be thought of as important in music they have sponsored concerts, documentaries, and so on.
The point shouldn't be that Garmin has sponsored athletes and teams. The question should be why does Apple have ZERO sponsored athletes and teams.
Additionally why do we see zero feedback from that group improving the fitness aspect of the Apple Watch?
To be honest though many of those questions and bugs relate to very edge case scenarios that are impossible on the Apple Watch and most other competitors. For example I've been doing a lot of treadmill running lately. I use my Garmin with the virtual run activity profile to execute the recommended part of my daily training plan, a plan from Garmin that is also adaptive, on my treadmill with Zwift.
My watch can transmit my cadence, speed and HR to my Apple TV running Zwift to a nice big TV I've got mounted to the wall. It's a great way to fit in the running with busy holidays.
You can find a million posts where people want to do this with their Apple Watches. Apparently Zwift tried to get the watch to do it but gave up. On a good day some people manage to use the Zwift companion app to get the Apple Watch to broadcast HR.
Likewise my Garmin can broadcast HR to anything that is not Apple Fitness. I can broadcast to Peloton, to Zwift, to whatever.
There are also a million posts out there where people wish the Apple Watch could broadcast HR to their bike computer.
People have commented that all outdoor runs are just outdoor runs on Apple Watch. You can't have trail running vs outdoor running as different sports as an example.
Meanwhile the watch as speaker is a mess on Apple. I've experienced it myself. I'll have my airpods in, start music on the watch and have it play on the iPhone speaker first.
In short more abilities, more complexity, more bugs.
I disagree. We see Apple having a presence and showing feedback loops with professionals as an important consideration in the markets that Apple happens to care about. We don't complain that Apple sponsors a symposium or features short films all made with Final Cut Pro. We don't complain that they highlight and pay for things that are "Made On iPhone."
The reality is Apple cares about those markets and the sports market is a straight up afterthought and the way the Apple Watch works, and the lack of improvements that professionals in those fields would suggest, shows.