Those old people probably had steady hours and earned reliable paychecks. That’s not how it’s done anymore. Employees work part time, if it can even be called that. A single restaurant has something like 200+ employees, and some can go weeks without having any hours.

Those senior employees were too expensive. They probably weren’t fired or laid off. They were probably phased out in a flood of new hires so they would quit and not collect unemployment. Nowadays your server could have worked there for 2 years and have a few months’ worth of experience or less.