Can I generate passive income on BitCoin
If you buy 100 bitcoins for $10,000 ($100 per coin), indeed you will always have 100 coins, you will never end up with 101. But if the price increases to $15,000 for your 100 bitcoins, you could sell 33.333 of them for $5,000 fiat profit, and still you would have $10,000 worth of BTC just like you bought at the start - a profit of $5,000.

You can increase the number of bitcoins for free if the price then drops after you sold some, lets say the price goes back down to $100 per coin after you sold the 33.333 coins ($5,000 at the time of sale), then you could purchase back 50 coins at the new price, leaving you with a total of 116.667 BTC