I think what will doom Bitcoin is the uncertainty around the identity of Satoshi. Imagine bitcoin growing by a few orders of magnitude, now it's 10s to 100s of Trillions. Is it close to becoming a world reserve currency? At this point, just who is Satoshi becomes a matter on the level of nation states.
Bitcoin grows by a factor of 100x, Satoshi is now a Trillionaire. He has vast reserves of money he can move around anonymously. Does he still exist? Well his coins haven't moved. Will the world be okay with the mystery?
So no one knows for sure of course but many suspect that early mining by likely Satoshi owned wallets (2009 era) yielded some 1.1m BTC, worth >$50B today.
So the likely reasons someone sitting in a notional value of $50B+ who hasn't cashed in any of it include:
1. He (or she) is dead (I believe the last confirmed post was 2012?);
2. He (or she) has lost access to these coins;
3. He (or she) has cashed in some wealth from wallets not linked to Satoshi; or
3. He (or she) is sitting on this mountain of wealth and not cashing any of it in.
There's the possibility of course that Satoshi isn't one person but several.
Let's consider (4). You would need to be an incredibly committed ideologue. We have ways now of essentially laundering crypto (ie by converting it to other crypto through a pooling mechanism that makes it difficult to identify the source wallet for what comes out).
It's stated that perhaps Satoshi fears government persecution (eg the tenuous connection to Wikileaks). To me that seems... unlikely. It's not like Satoshi controls the network. Lots of people hold crypto now.
Maybe Satoshi just really likes his, her or their privacy. But given that wealth... (1) or (2) become increasingly likely as time goes on.
Bitcoin grows by a factor of 100x, Satoshi is now a Trillionaire. He has vast reserves of money he can move around anonymously. Does he still exist? Well his coins haven't moved. Will the world be okay with the mystery?