This trend is pretty obvious in the US as well. Just go to a RC and see the elderly seating section. It used to be fairly small, now I've seen places with huge swaths of seats reserved. Lots of grey hair at the local KHs.
I'm pretty sure the WTS is aware of the trend and while they are using videos and pushing kids to get baptized earlier, its really not enough. Many very restrictive and conservative fundamental Christian groups use a variety of youth programs to keep their young folks at least interested. What does the WTS do? Make videos. Really nothing else.
If they wanted to make an impact, they would organize youth groups, have an elder assigned as a "youth pastor", organize activities beside just FS and maybe even have a section of the mid-week meeting where they break off into various special interest groups (youth, elderly, parents, singles) and have programs directed specifically at their needs as opposed to the one sized fits all type of programming they do.
Because the organization has always been focused on recruitment, they have neglected retention. And because retention is low, they have nothing in the pipeline for the future.
The other thing the aging trend does beyond losing members is losing those who can step into leadership positions. Which puts pressure on older elders to do more, in turn burning them out or at least creating apathy. It's a vicious cycle of decline.
They don't seem to have anyone with a creative bone in their body that can come up with different ideas. They go back to the only thing they know, beat their members.