Yeah because those that acquired bitcoin at say $1 or $10 per bitcoin took a huge huge risk with their money. Back then it was very risky investing in bitcoin because the project could have easily been scrapped and losses would be 100%.
This is similar to people investing in Tesla during IPO. Stock was cheap but there was so many EV company failures that it was very risky to invest in a new EV car company.
So now that Tesla stock is in the trillions, does it create inequality to those that bought early and those that want to invest now? Yes but the early people took on greater risks.
It is true that people who invested in Bitcoin and Tesla very early took huge risk. When they bought in both were very new. Bitcoin could have completely failed and many people thought electric car companies like Tesla would not make it. Early investors could have lost all their money. Because they took such big risk so now they earned huge rewards. Now that both Bitcoin and Tesla are successful and more stable investing in them is much safer. However since risk is lower potential to make massive profit is also lower.
It is not really about inequality. It is just how investing works. High risk can lead to high rewards and lower risk usually means lower returns.