You can't neglect something, then turn down fixes because they won't happen fast enough. Fast enough wasn't a concern during the period of neglect, so a sense of urgency is playacting. The optimal solution is to pay properly, and if temporary things have to be done (rewarding people for not retiring, paying a premium to develop/import some controllers quickly) then so be it.
What a "3-year training process" and the fact that accidents come at random does is create a grace period for profiteering. They would neither get a fast enough return on investments in staff, nor see fast enough losses from disasters resulting from staffing neglect, to see any problem with both not investing in staff and with finding savings in neglect.
Problems during the transition period between starting to do the right thing and when you will see the effects of that thing are good problems to have. They go away by themselves.