I agree about system design, but I think - especially in the context of your networking example - the complexity lives below the OS and not a case where it's a lack of effort.
Networking protocols, connections, error states, etc are inherently complex and require equally sophisticated handling that linux may not always do. Some software chooses not to handle at all and expose directly to the user - but others like KDE simply lack the millions of dev-hours of polish that Windows and Mac have.
Is it that simple though? There could be so many other reasons. Maybe the particular issue is related to a specific hardware or network configuration that the developers have never run into or can't reproduce.
Linux needs polish for sure, but given a finite amount of time, energy, and money the reasons are likely more complicated than "they don't care"
Networking protocols, connections, error states, etc are inherently complex and require equally sophisticated handling that linux may not always do. Some software chooses not to handle at all and expose directly to the user - but others like KDE simply lack the millions of dev-hours of polish that Windows and Mac have.