ohh dear. BTC price goes up and you can biy split parts? like 0.00001BTC equivalent of x amount of money. you not need to buy one BTC, even if it's desired. and thats why.

Explain like I'm 5: if BTC is scarce/finite, how can all of us have/hold BTC in the future when all of it will have been mined?

Like the title says, I genuinely don't get this. If there's a finite amount of BTC then exactly how will all of us be able to hold BTC to trade/buy/sell as it was originally intended? Doesn't that mean we should all just jump on the bandwagon and start collecting? Because if it's similar to gold, then in short, it's about first come first served, and those who have it the earliest will always be the luckiest. Except none of us are going to find a random gold mine anymore.

Basically how will people be able to get into BTC in the future and use it as a currency, considering its scarcity? I genuinely don't get it.