I don't think Twitter would fall. Elon may have made a decision backed by many to fire some former Twitter employees, but it would take like between 5years to 7 years to determine if his new company, Twitter would stand the test of the seasons, before considered as a failure.
Although, Mark of Meta has launched a competition network in the name of Threads, just to wake Elon from his slumber of just owning a company, it is yet to be seen what Elon has as reply to this and what new incentives he is incurring to see that Twitter isn't a failure in all entirety.
Twitter was a popular social media for celebrities. But Instagram was a rival of Twitter but now Mark Zuckerberg has brought Threads as an alternative to Twitter. Twitter is now under a lot of pressure. If Elon Musk wants to develop Twitter, he needs to adopt more new strategies to move Twitter forward. But maybe it is possible with Elon Musk. But since Mark Zuckerberg has been running Facebook since the beginning of his business. So I think Mark Zuckerberg has more knowledge about social media management than Elon Musk so it will be hard for Elon Musk to compete with Mark Zuckerberg.