4) no pay for unused sick or vacation time - this is why you see cops make $400k when you look at state reports. These are retiring cops getting paid for unused vacation and/or sick time. Though most new contracts limit this already.
The problem is that absent the pay, there is no benefit for a public sector worker not to take every sick day - they are regarded as extra vacation, not time to use if you are actually sick.
In the private sector, one would get an undesired reputation if you kept taking sick time and using it for vacations, home repair, etc. Your chances for advancement, avoiding layoffs, getting critical assignments, etc. would be diminished. As such, there is a "cost" to taking sick time or the private sector worker, and a value system of "sick time is fo when you are sick" evolves.
There is no cost to taking sick time for a public sector worker as they are protected by union/seniority rules, and their career is not enhanced by not using all of it absent a payout at the end. Oh, and that payout is at the higher rate they are earning at retirement time - perhaps days at a captain's salary for those sick days they banked as a first year officer or teacher. It's like if a firefighter in Boston gets disabled moving a file cabinet while filling in for a higher ranking officer, (s)he gets disability/retirement at the pay rate of the person whose job (s)he is doing. Working above your normal pay grade has proven very dangerous in the Boston FD, with the proportion of disabling injuries suffered on such days out of proportion to the percentage of days worked above pay grade.
And let's not forget the Lexington clause for teachers.
I am in the private sector and was recently told I have up to 3 weeks additional "Covid sick time", but it was made very clear that this is to be used only iI am actually sick; I have not been granted three weeks extra vacation. I have not seen a single person abuse it. Think that would happen in the public sector absent banking of the value of the time?
It's not because private/public people have different levels of integrity, but because they are programmed in vastly different work enviornments.