Hardly appropriate to average the pay of all university degree holders, and compare that to teachers pay. Would expect most teachers have a BA.The average salary for Ontario degree holders 2 years after their undergrad is $49,151 which would correspond to a first year teacher. Teacher numbers from the agreement linked are well within norms.
http://cou.on.ca/publications/reports/pdfs/2011-survey-highlights---ontario-graduate-employme
http://www2.macleans.ca/2013/01/16/the-million-dollar-promise/
"A closer examination reveals the problem with such generalizations. Using the same data, a female English undergraduate degree holder earned $30,762, well above the $19,000 of a female high school graduate, but below the $32,343 earned by male high school graduates. The numbers for film studies majors were lower, $26,172 for men and $25,447 for women. Lower still were music graduates, at $19,348 and $20,814. Even science graduates don’t do as well as most people imagine. Physics graduates earned $40,216 for men and $31,545 for women. Contrast these numbers with the much higher wages for civil engineering ($60,000 for males, $49,924 for females), business administration ($48,405 and $39,295), finance ($55,919 and $42,182), nursing ($53,764 and $47,985), law ($56,975 and $50,000) and pharmacy ($88,425 and $71,493). While gender is obviously important, degree choice can matter as much as the decision to go to university in the first place."