Oncall can show up after the fact. You take a job paying $X. Two years later, people decide that 24/7 oncall is necessary and suddenly now you are required to

Oncall can show up after the fact. You take a job paying $X. Two years later, people decide that 24/7 oncall is necessary and suddenly now you are required to perform this 24/7 oncall. Your pay is not adjusted. You have no say in this new job requirement. This oncall is unpaid (your compensation hasn't changed). >500,000 compensation is also highly unusual, even at very well paying companies.