the original saying about bad apples is that one spoils the barrel, which applies in some organizational cases.
Sure you can't blame a million middle managers, because they are all in different barrels, but congress people are in the same barrel, and if one is corrupt we might assume that non-corrupt ones will be corrupted over time by exposure.
Many systems can be set up to ease spoiling, thus creating a two-tiered problem, when the teachers are all bad because the system promotes bad teachers you can't fix it just by fixing the system because you have a crop of teachers in their barrels waiting to rot any newcomer and also rising to positions where they can put regulations in place to ease rottenness in the future.
I think we're talking about a difference in timescales. My experience is that culture naturally converges to incentives, but very slowly.
If we were to evaluate teachers in ways which didn't align to tests (or not at all), put in mechanisms to fire bad teachers, added transparency and accountability (so parents know what's going wrong and can try to advocate to fix it), etc. we would have a whole new teaching culture... circa 2044.
A faster reboot is possible, but with more disruption (e.g. wholesale firing). Disruption is harmful in several ways, from impacting morale and stability (making it more difficult to bring in qualified people), to having experienced people leave, to simply taking time to learn how to work in the new order. Whether a disruption is warranted depends on the level of organizational dysfunction.
The current set of dysfunctions in schools specifically are grounded in a narrow tests which were implemented in 2002. Schools have increasingly broken, as anything not in Common Core was increasingly ignored, and schools competed on the only measure they were evaluated on.
Sure you can't blame a million middle managers, because they are all in different barrels, but congress people are in the same barrel, and if one is corrupt we might assume that non-corrupt ones will be corrupted over time by exposure.
Many systems can be set up to ease spoiling, thus creating a two-tiered problem, when the teachers are all bad because the system promotes bad teachers you can't fix it just by fixing the system because you have a crop of teachers in their barrels waiting to rot any newcomer and also rising to positions where they can put regulations in place to ease rottenness in the future.