I wouldn't expect too much change right away after a lay off that size. Any decent engineering team will have processes, workflows, CI/CD, etc... in place and if all the engineers went away today, most places would still run just fine for a while, maybe even a long time if the systems are set up correctly. The question becomes what happens next? How quickly will they be able to leverage new advantageous technologies? What happens when that rare thing breaks and you have no institutional knowledge? How do you solve difficult problems like content moderation? I'm curious to see where Twitter will be a couple years from now in terms of how it's engineered. I would expect a slow decline in expectations and results.