This change in the mass consumer psychology that is so important and relevant in the world today will lead to a liquidity crunch. Central banks usually solve the problem of a liquidity crunch by printing money and lending it out cheaply but they won't be able to do this as faith in fiat currencies will already have been so severely degraded by Bitcoin's ascendancy. There will be no answer to people becoming more prudent with how they spend their hard earned bitcoin. It will simply shrink the economy.
I don't get what you mean by when a consumer's psychology will be changed from buying less. I mean they will prefer to buy BTC for long-term investments but they still have to spend money on their daily needs which means they don't have to spend all of their money in BTC but have to keep some money in liquid form that they could use to meet daily expenses. And how the change in the psychology of consumers is going to crunch liquidity and which liquidity are you talking about, I mean if you are talking about fiat then you also mentioned such a problem can be faced in fiat via lending and printing more money, etc.
Overall, people can't just survive by holding BTC in their wallets, they need food, a roof, have to pay bills, etc. So to meet all the expenses they can't just rely on there funds in the form of BTC because in the long run BTC does give profit but in the short term BTC can also make you loss. And a person with mindset of keeping no funds for emergency cases, is consider idiotic because investing in one coin is extremely risky especially when you are spending it all. Even the emergency funds.