This wouldn't be treating them the same as trillion dollar corporations, this would be treating them worse. The original Jacobin article says:
> And unlike the federal tax, this tax would be on the schools’ total endowments, not just the income they make from it every year.
I think it's unlikely this bill will pass because if it does, it would be tax-advantaged to operate a for-profit corporation for the sole purpose of making yearly donations to a school than just giving the money to the school directly. 21% corporate federal income tax + 8% massachusetts state tax of a 5% yearly return is effectively a 1.45% tax on wealth which is a better rate than schools get (there is no corporate wealth tax in America).
Even if one agrees with taxing universities the same as any business, this particular implementation treats private universities worse than businesses.