Assuming that you are correct that things are breaking more at Twitter (which I'm not sure is accurate to begin with), how do you know that is due to "lack of engineering talent" and not due to higher pressure to deliver features?
As anyone who has operated a software system knows, the #1 reason things break in production is new code, and from a third-party observer with no inside knowledge it certainly seems like more changes are happening at Twitter than ever. This is orthogonal to layoffs, though.