Common language says that a wireless router is the general case for a "router". While that's not technically accurate, it also follows the rules you just gave.
"Common" is not the same as "popular here", it has to apply to other places and social groups.
It also has to be a language, which means structure and stability.
Language drift is something societies have been fighting against for thousands of years, just look up problems the French have had. And of course, we all (except a few) speak Latin, just drifted into different dialects.
On the other hand, if you are talking to someone that speaks a different dialect, you need to speak their way if you want to be understood.
If I visit some offices, I do call the PC a "harddrive" and the monitor a "computer"!
Which means if you are here, you should speak our language, not the one from the coffee shop... 8-)