was arbitratry for bitcoin also? i remember 21M come up from a math equation or some other calculation
50 BTC every 10 minutes, halved every 4 years --> 21 million BTC total
Other coins use different numbers and different distribution plans. Many coins are not capped.
so satoshi started from the block reward, to build bitcoin
Not really. You can also start from the total number and then work backwards.
What do you mean? Start with 21M coins premined, then "desmine" the coins along the way?
And topic:
It deppends about what demands the dev wants to serve. It depends about the confirmation time(longer or shorter), the expected market cap, when the mine phase will end, etc..