Additionally the scale of this bubble is much larger than 2008.
The scale of the bubble and the effect of it bursting aren't the same thing. It depends on what underlies it. The stock market has run well ahead of its fundamentals, but since most people aren't buying on margin and aren't taking loans out on the value of their stocks slashing the value of their stocks doesn't have too many knock on effects other than making people with 401Ks feel less wealthy than they did before the crash. It is like the dotcom crash in that respect. This wasn't true for the 2008 crash, because the mortgage market is ALWAYS on margin - and things got pretty crazy before the crash so the "margin" was even thinner than usual.
The unknown for the upcoming crash are the players who ARE investing in the market on margin. I'm not talking ordinary people like you and me, but big investment banks, hedge funds, and the latest swamp that's probably going to light the match that sets off the next crash, private equity. There is so little regulation in PE so no one really knows all the sources they're getting the cash, on what terms, on what margin, etc. so if they get squeezed the answer to the question "who did they borrow from" will determine how much it spills over into the economy as a whole (by this I mean spillover beyond just paper losses in 401Ks)
What is worrying is that a lot of state pension funds have started investing in PE, and the ones who are heavily into it could really devastate the employees who pay into those funds (and the state's taxpayers who will be called upon to make up the difference) Insurance companies are also rumored to invest in PE, so a crash could provide a double whammy of making our home insurance go up even more than it has been.
The reason safe havens tend to fail when there's a crash is the big players need money to make their margins and their forced selling of bonds, gold, crypto basically any liquid or semi liquid assets they have available drives down the prices of everything until the panic subsides. That is, unless the government steps in with another bailout, picking the winners and losers (and the winners will already know they will be winners in advance, which is why they keep inflating bubbles again and again because they know they won't have to bear the losses when they screw up)
