It's called salary compression and it's always been there.
Pay compression (also referred to as wage compression or salary compression) is when employees who have been in a job for a long time makes less than new hires in the same position. With pay compression, there are small differences in pay that ignore experience, skills, level, or seniority. You see pay compression happen when starting salaries for new employees in a particular job title are set too close to the wages of your existing workers. In really awful circumstances, the starting salaries exceed what your current employees are earning, even if your tenured employees have more skills and experience.