I've been told by folks that should know that there are no countermeasures that can stop the newer MANPADS.
At low altitudes, which is where MANPADS are used, you are correct. The bloody things are simply too fast and too smart.
Totally different story if you've got 10,000 feet between you and the ground and someone hoses off a MANPADS missile - but then, almost nobody is stupid enough to try that. Stingers have a 10,000 foot ceiling, but their kill percentage drops off notably with targets over about 5,000 feet.
There's always countermeasures. They may not be cost effective, but it's always possible. For example a powerful laser could just burn out the detector on the sensor of the missile. But it's true that decoying the missile seeker, or even just causing it to break lock, is getting more difficult. The missiles won't go after something that doesn't both "look like" a target and act like a target. It's difficult to get false targets to behave in such a manner. Denial (IE blinding the seeker) is more difficult with a passive seeker, although even an Radar seeker can go into a home on jam mode if it's blinded.
One possibility is a towed decoy, which can be made to both maneuver like and "look like" the targeted aircraft. These work well if there's only a single missile going after the target, but if there is more than one, then you need more than one decoy, since the decoy is likely to be killed.