Nobody wants to hire juniors and train them to be seniors because there are very few incentives to hire them.
Partly because projects are sold at such low margins that they don't allow for tutoring. Or the customer plainly states that they want 5 engineers with 10 years of experience each. It's a hard sell to make that 2 10 year guys and 8 juniors instead.
Partly because the junior will bolt to a higher paying job as soon as they've learned enough. People don't stick with companies for the long haul like they used to. Even if the pay is good, people just get bored and switch jobs.
Partly because projects are sold at such low margins that they don't allow for tutoring. Or the customer plainly states that they want 5 engineers with 10 years of experience each. It's a hard sell to make that 2 10 year guys and 8 juniors instead.
Partly because the junior will bolt to a higher paying job as soon as they've learned enough. People don't stick with companies for the long haul like they used to. Even if the pay is good, people just get bored and switch jobs.