Well… the FB IPO went great for existing (vested) stockholders.
If your stock doubles immediately after going public, you just lost a ton of money and were probably grifted by your market-maker.
For famous companies that are already in the public mind I have no idea why they go the traditional IPO route (I'm not sure what SEC/market regulations require). Why not something like offer 10k shares at a $100B valuation see if anyone bites? Then go to $90B, and so on until you sell your entire offering. There is so much dead money out there that would buy $20 shares of twitter for any insane valuation and they are just leaving it on the table.
Google tried something similar with the reverse dutch auction