Why not more wireless connections?

Because too much wireless , wireless headphone, wireless speakers add  to the  electrical background too much already...

More technological improvement sometimes is less...

And a cable can substract some quality or add some to the final result...

https://www.news-medical.net/health/Does-WiFi-Affect-the-Brain.aspx

I think the best, most secure, most reliable connection is always wired.

When you listen to home audio there are no diversions and your ears are extremely sensitive instruments. Nuances of sound characteristics and noise  is incredibly obvious. So, the absolute highest possible quality of interfacing is required. 

Wireless stuff isn't even close to competing with wired stuff.