Its not even really a short term boost for the stock. Layoffs are seen as a massive red flag for the stock and news of them is usually followed by a drop in stock price.

That could be counteracted by funneling money to shareholders (dividends or buybacks), but since layoffs are expensive, you don't actually have more money to funnel to shareholders. You have to pay a ton of severance, and you will need the liquidity in a few months when you rehire anyway.