I'm talking about starting from Heathrow, I dont know what it will be like transiting. While I'm impressed at the effect it has had, you are right in that what they have done is proved that if they want to do something about it, they can, and that makes it even worse if they dont do the same thing in their other airports.
It's not neccessarily about installing extra scanners anyway- more about employing enough staff that all their existing scanners can be open.
Heathrow has had so much bad press recently I guess they felt they had to do something, wheras other airports dont seem to get criticised as much so maybe there's not so much incentive for them to do it there.
30

greencelery
31

nerb
If things have improved now, it means they started the process a long time ago - it won't have much to do with recent press. That's my point - it takes time to install new equipment and hire and train new people, whereas limiting carry-ons can be done with immediate effect.
Regional airports get bad press too - you just won't be aware of it down there.
Pro tip