The employer isn't liable for the pension at all. Neither is the employee. All they do is pay into the fund. Instead, there is an entirely separate legal entity (the pension fund) that controls and distributes the assets. The fund releases reports regularly on the health of the fund. The contribution calculations are usually included in those reports. The investments by pension funds are usually in long term infrastructure assets like highway 407 in Ontario, or various property management companies such as Cadillac-Fairview.
https://en.m.wikipedia.org/wiki/Ontario_Teachers%27_Pension_... the Ontario Teachers Pension Plan is probably one of the best examples of a well run pension fund. All public employees in Ontario, as well as federal employees are all part of a union, whether it be OMERS, PSAC, CUPE, caisse or otherwise. These unions protect the employees from the 4 year swings of governments and instead look after the long term health of employees.
I suggest you research the laws surrounding pensions in Canada. Answering the questions properly here is too lengthy, but they could probably be answered by 30 minutes of research. Pensions are incredibly powerful for looking after retirees. In fact, Canada has a federal pension plan called CPP which pays out to all Canadians based upon their contributions over their lifetime. Pensions are not the enemy my friend, it's elected representatives who look out for their short term interests instead of the health of their electorate.