It makes a lot more sense for Facebook to change the name of the parent company — given the actual and potential proportion of their revenues from Instagram and WhatsApp — than it did for Google to change to Alphabet given that Alphabet is still mostly Google in terms of making money.
However, the timing makes it look like a ploy to distract from current controversies (although I don't think it is a ploy), and the name Meta is going to look really stupid if their whole Metaverse thing doesn't work out.