Actually engineers often give watt measurements for the individual drivers, esp. mids and tweeters as this is generally an easily discovered thermal limit. bass drivers have to contend with enclosure design and while they also have thermal limits their excursion limit usually comes into play.

Where it gets tricky is, as you say, once the drivers are integrated into a loudspeaker system.

Most tweeters can only dissipate a hand full of watts in a continuous tone test - 10 - 15 would not be unusual. So how can they survive? In music they only get a fraction of the signal and that signal typically peaks and dips, giving plenty of time to cool between peaks. the same is true of the other drivers, to a lesser extent.

To put it simply, I've NEVER blown a tweeter (or anything else) from having an oversized amplifier.

Match the loudspeaker to the room, feed it from a decent amp, all should be well.

I've had very nice amps from the oreint, North America and Europe that gave no trouble, and also not so nice stuff from most of those places too. Country of origin is no assurance of quality.