Now the reason why Bitcoin will change a lot when it hits $100k is that a lot of it's investors will learn to trust Bitcoin more and more people who have not yet invested will have some kind of conviction to start making investments
Trusting Bitcoin shouldn't rest on the shoulder of the price surpassing $100k because it doesn't mean anything and however regardless of any price I see no reason why people will not have a trust on Bitcoin and also in terms of trust, price is never an instrument use in trusting Bitcoin, so actually I don't really think if trust is the reason why most people are focusing too much on the price hitting $100k because you should no that people will always speculate about Bitcoin, so even if it gets to $100k the same people will extend there level of expectation to the price of Bitcoin reaching either $150k or even more, so I don't think trust is the issue.
A new investor needs to have believe in bitcoin that it is a good investment worth throwing some value on before he can take his bitcoin investment serious, otherwise he might not have the passion and zeal to invest in bitcoin and grow his bitcoin investment overtime. As long as you have the believe that bitcoin price will be more on a uptrend than downtrend in future that's enough for you to build and grow your bitcoin investment for long term.
Another thing is if you see bitcoin as a store of value where you can use to save your funds to avoid it depreciating overtime due to inflation, you will not bother about the price reaching 100k because you are after the future.