50 weeks?

How about:

-Vacation time is not paid time while maternity leave is time the employer has to pay for.

-If working does accumulate vacation time (meaning it is paid) it's a fixed perk that the employer can take into account and knows when hiring you

-You must still always negotiate when you are going to take that vacation, you can't just start at a new job and instantly take paid vacation time.

-2 Weeks != Maternity leave

"maternity leave is time the employer has to pay for"

Not in Canada. Maternity leave is funded through the federal Employment Insurance program. The only obligation the employer has is to hold the job for a certain period of time.

There are employers that top up, to varying degrees, what EI pays out (maximum benefit is ~$500/week, and taxable).

Vacation time not paid??

Probably US.

2 week vacations are almost always paid in the US.