I don’t think anyone has the budget for that anymore - not even the big companies. It’s two years of negative $ output for the $ you put in and after those two years the junior dev leaves anyway for a more senior position.
1) it’s a waste of resources for seniors to be doing the work that the juniors and 2s can do. Hunting down infrequent or low priority bugs, fixing small layout issues, etc. they’re perfect for someone paid less and growing and learning the codebase.
There is *always* plenty of junior-ready work and the day a week of work to schedule, prep and help those juniors to do it pays dividends.
2) a Junior leaving because you won’t pay them, have a toxic culture or won’t give them a promotion when it’s time speaks more about a broken company culture and one of a style that’s rampant in the tech industry and business at large than it does about loyalty and willingness for the employee to stay at the company.
Good leadership and skilled organizers can easily solve the problems you’ve listed; and, even better, create a culture of longevity for all the employees at a company, not just the juniors.
Speaking as someone that has worked for companies that give a shit about their workers and who helped raise me up from a low SDE.
These are tasks that in the current environment often get pushed back for "later" indefinitely. These tasks aren't un-resourced because the company isn't hiring juniors, the company isn't hiring juniors because they no longer have the funds for small fixes.
You're going to have to teach them about the unique frameworks and processes at your company, but you have to teach seniors about those things too. Unless you're doing something really unique, juniors don't need to tie up senior devs "for months". Remember they can help each other, too.
this could be an amazing time for companies to pick up more experienced engineers at junior position/salary. but they aren't biting.