$1 trillion dollar market cap for Bitcoin is such an important and powerful statement, that it will definitely result in not only capital parked in Gold to shift towards Bitcoin, but pretty much all legacy assets will start bleeding to a certain degree.
After that $1 trillion dollar milestone the "slow" capital (the braver institutions, governments, hedge funds, royal families, etc) will start to massively inflate Bitcoin's price towards even greater hights. It would be a tremendous achievement when governments will finally start stocking up Bitcoin instead of just Gold.
It's actually quite 'easy' to see Bitcoin hit a market cap of $1 trillion. Bitcoin at $60,000 with a circulating supply of around 18 million coins at that point is only a matter of time. Realistically, we're just another bull run away from doing it.
Yeah we can hit the milestone by the next halving, or even before that if it goes into rocket mode earlier. After the $trillion psychological barrier is hit, I expect a big FOMO by big players. Most likely big players will use OTC but this will translate in the market prices short after since there is always someone that knows about these huge OTC deals but they don't have access to OTC liquidity so they go to Coinbase or whatever to pick a bunch and the price rise starts.
But still, I think goldbugs are too deep in denial. 1 $trillion may not be enough. Perhaps it takes half of gold marketcap's for them to wake up, or even as long as gold has a bigger marketcap they will think BTC is just a temporal trend which will go away. I just can't wait to hit the first trillion, once we hit that the rest will happen pretty damn fast.