The StackOverflow devs being replaced were never going to become real senior developers no matter how much time was given to them. There is an entire cohort of people who were told to go to college for programming because it was an easy way to make good money, who did what they were told while having zero interest in it and never touching a line of code outside of work/school hours. Those people were never going to understand actual programming, all they were doing was copy-pasting code for a paycheck. Does it suck for them that they're being replaced by automated copypasting bots, yep. But frankly speaking nobody should've ever been paid 6-figure salaries to copy paste snippets from SO and jam JS library legos together in the first place.