Serge, I do what I can to allow the unwanted resonant energy to travel away from its point source as expediently as possible. And I propose others do likewise. Well, unless I don't like them.
Mfg'ers for the most part do nothing about it because I suspect like others they know nothing about it. Gotta' remember that the entire world is committed to the "isolation" methodology because it's just so much common sense. Actually, it's worse than that. Nobody does nothing about it which implies everybody is doing something about it and that means by their designs, construction, materials, and executions they most always make the situation worse not better. Even in the case of a mfg'er's stock footers, their remedies will most always and unknowingly trap the unwanted resonant energy within the component so somebody like me has to work around their significant shortcomings. And it ain't so easy sometimes. But if you think about, it's pretty difficult to remedy a problem we don't even realize exists or remedy a problem that flies in the face of "common sense" that's been handed down over the generations.
But the bottom line is, vibration isolation with its focus primarily on floor-borne vibrations and the remedy is to isolate sensitive components from the floor, is nothing but folklore. But common sense dictates that speakers (and the earth) vibrate and if their vibrations enter the floor, then they're coming straight for my components in my rack and they must be stopped. Common sense right? Sure. Except that floor-borne vibrations were never the performance issue.
Even when it comes to turntables which are a nightmare to remedy with their layer upon layer of isolation. With TT enthusiasts there's always the typical story of one hosting a party and a 400 lbs. guest dancing in front of the TT causes the stylus to jump 14 grooves and the host freaks out. What's the solution? Common sense dictates isolation. And guess what? It works. Now the 400 lbs. guest brings their 300 lbs. friends to the party and can dance in front of the TT 'til the cows come home and the stylus no longer jumps a single groove. This is what some call performance in high-end audio.
What they don't realize is that the 400 lbs. guest dancing in front of the TT has zero to do with vibrations but rather has everything to do with shock and impact which is an entirely different subject matter and has no place in high-end audio. Besides, shock and impact requires absorbtion (think isolation) which has zero to do with real performance. Well, except for TT's used at parties.
IMO, it is exactly this typical story that popularized vibration isolation in high-end audio. Golly, if isolation worked for George's TT down the street, maybe I could try hanging my 150 lbs. amplifier from the rafters using bungee cords which may or may not impact performance good or bad ever so slighty. But as usual, this "common sense" just starts flying everywhere.
And yes, I'm well aware that some will claim to hear genuine improvements and in some cases they may but the improvements are never large. But that's a whole nuther story.
BTW, I really do try to steer clear of most vibration mgmt threads as they usually become bottomless rabbit holes.