Partly blame feminism. Teaching primary school used to be a "woman's job" that was respected and admired by society. Some of the best and most dedicated women did it for the social prestige even though it was not well paid. Then feminists said it was too low level. Women should be highly paid administrators and lawyers. Now it's mostly the least bright and motivated women who become teachers. They are gullible SJWs who are easily influenced and lazy.