TWTR started trading 8.4 years ago at 45/share (after being priced at 26). SPY was priced at 180 and is today at 440. Gold was down near 1200 and is now at 1900. Twitter grew in value at 2.2%/yr before inflation while the S&P index grew 11%/yr. Factoring in the IPO pop (which screws the VCs), Twitter would have grown at 9.1% per year.
(The banks also have strategies that earn them more at IPO, so they probably are earning slightly more than 10% per year on their investment.)
In short, Twitter is not keeping up with the broader economy at Musk's price. You're telling the investment banks, mutual funds, and most-senior vested employees that their company has the same worth as a low-risk government bond or a bar of metal.