No, 1 BTC won't be enough to become rich. Imagine you don't have any properties and goods and that you have to build your entire financial life with just 1 Bitcoin. The maximum you will be able to acquire with that money is a house or a car. Then how are you going to get rich this way? From where are you going to get money to maintain a house or a car? How will you generate income for a living? A single Bitcoin isn't enough, even if you live on the poorest nation in the world, I suppose...
If thats how you define 'rich' maybe some are still consider themself as poor or average. If they are they comfortable in life, they buy the things they like and they are happy with it, they surpassed what they call rich people. Also if they are planning to hold this 1
BTC they can get a higher or lower price, its the owner risk to take. Like ETH, BTC is also worthwhile long-term investment. However, they are extremely volatile. That means large price movements over short periods are common.
This 1 btc can also help you to try other investment not only Bitcoin. What I mean is in real life investments.