Millions of Superboxes and various digital picture frames say different.
Well yes, but those won't get Google's new updates either. Open ADB on 5555 was a problem we solved almost a decade ago and these devices are still vulnerable. Even further restricting ADB in the latest version won't do anything to prevent that.
Kimwolf exploits vulnerable Android Debug Bridge (ADB) services. Many low-cost TV boxes come "pre-infected" with proxy SDKs; Kimwolf then scans these residential proxy networks and exploits the devices within minutes as it propagates.
https://www.cloudflare.com/learning/ddos/glossary/aisuru-kim...
This is like saying that SSH is insecure because some device vendors install SSH, permitting root login with a default password of 'root'.