That same quick googling would have told you that it is enough to have a BA degree and to pass a fairly short teachers prep program. You are comparing apples and oranges.

$110,000 is the base salary. Add to this pension contributions almost completely funded (granted this is no longer the case for the new hires), a retirement on a full pension at 55, and a stable job. Good luck having all of this working as a software engineer for a private company. You can be made redundant at no notice, and risk always carries a premium.