It can't be because conservatives run Beacon Hill; they haven't in generations.
There are at least two answers to this question; both of which are historical. We often do not realize how centuries old cultural practices influence modern outcomes.
The first has been a constant theme in this space - the New England town meeting - a system of self-government agreed to before the first Pilgrim supposedly set foot on Plymouth Rock. Imagine a system where the school "bureaucracy" consists of half a dozen of your own neighbors, volunteering their time and chosen at large, to run the schools they send, or will send, their children and grandchildren to. The "legislature" they answer to is all of you gathered at an annual or semi-annual town meeting. The "executive" is three more of your neighbors, also chosen at large, to be Selectmen. The Athenians, when they saved Western Civilization by taking on the Persian Empire at Marathon, did not have a more efficient or accountable system.
The second is almost as old as the first. The Old Deluder Satan Act was passed by the Massachusetts Bay Colony Great and General Court (their legislature) in 1647. It speaks for itself, and is worth citing in its entirety:
It being one chief project of that old deluder, Satan, to keep men from the knowledge of the Scriptures, as in former times keeping them in an unknown tongue, so in these later times by perswading from the use of tongues, that so at least the true sense and meaning of the Originall might be clowded by false glosses of Saint-seeming deceivers; and that Learning may not be buried in the graves of our fore-fathers in Church and Commonwealth, the Lord assisting our indeavors: it is therefore ordered by this Court and Authoritie therof;
That every Township in this Jurisdiction, after the Lord hath increased them to the number of fifty Householders, shall then forthwith appoint one within their town to teach all such children as shall resort to him to write and read, whose wages shall be paid either by the Parents or Masters of said children, or by the inhabitants in general, by way of supply, as the major part of those that order the prudentials of the Town shall appoint. Provided that those which send their children be not oppressed by paying much more then they can have them taught for in other towns.
And it is further ordered, that where any town shall increase to the number of one hundred Families or Householders, they shall set up a Grammar-School, the Masters thereof being able to instruct youth so far as they may be fitted for the Universitie. And if any town neglect the performance hereof above one year then everie such town shall pay five pounds per annum to the next such School, till they shall perform this order.
As for today, are we not still subject to being "...clowded by false glosses of Saint-seeming deceivers" and in fear that what we have learned over the centuries will "... be buried in the graves of our fore-fathers?"