Except you are conveniently ignoring the other peice the employer contribution.   When calculated together the PERA Employee is contributing much more early and reaping the benefits of that contribution later.   And a big part of that contribution is a lower salary leading to a lower overall payout from PERA even at a higher percentage.   

Example Person A can take job A in the private sector at $50000 or job B in government for say $45000.

Job A is for damn sure going to give bigger than 0-2% COLA and far bigger than 0% merit pay increases to employees most years.

Job B if lucky will get 1% COLA year to year.   They can technically get merit increases if the legislature funds them but that's happened 2x in15 years.   So even before looking at retirement there is an issue.

Cost to employer

Job A contributes (both employer and employee) 3100 X2 6200 towards SS 
Job B contributes 3600 employee and $9000 from the employer.   
Job A $53100 Job B $53100. Pretty close right