When it comes to layoffs, no one wants to be the first company to do it, and no one wants to be the last company to do it. Once a few of the industry leaders started doing it, it gave others top-cover to start the process. At this point they need to do the layoffs so if they report bad sales numbers for the quarter they can say "we saw this coming, thats why we did some layoffs alredy. we should be good now". And if it turns out the didn't "need" to do it, they can just hire the people other companies laid off.
This is how I see it as well. Many might have wanted to do it, but they didn't want to be the first. As soon as the big ones started doing, even just one or two, the floodgates opened and now everyone can blame it on "everyone else doing it", "it's the environment", "the economic reality", etc.
