Surprisingly enough, one of the locations where speed contol is absolutely required is during the Hajj season at JED.
Many times aircraft in close trail to three parallel runways, and it works like clockwork.
Then, one day I receive a request from the JED approach controller...
EAN3037, are you a TriStar?
Affirmative.
Can you maintain 200 knots until five miles final?
210 if you wish.
Even better, thank you, call the tower.
And yes, it is possible with the 'ole Lockheed tri-motor, if you pay attention.
The point to this little story is...if ATC folks want maximum co-operation as regards requested speeds, all they have to do is ask, BUT they do need to state when that speed is no longer needed.