Hello Elle,
Who knows ? Perhaps your grenade has killed anyone susceptible to rise to the challenge .....! :))
Seriously though, I can only speak about my experience in France and it is true that the teachers are much less under pressure, as you say because of a reduced number of children in each class - say 25/28 as opposed to 32/35.
They are also well chosen; only highly qualified teaching staff with extremely good credentials are selected in those schools which can afford to pay them well - thus they seldom go on strike whereas the state teachers usually take a strike action two or three times per term!
Another aspect is the natural selection that is (unfortunately) made at base, mostly because parents who can pay are usually (but there are exceptions of course) people who have been well bought up themselves, and who have given their children the same basic home education to their kids - less hooligans!
This is how I view it, but I am willing to stand corrected !