Actually the coins are a reward for signing the block.

You "mine" the block, not the coins as you need to guess a number between 0 and infinite to have a block signature that starts with a bunch of zeroes. Then you get the coins as a reward for mining the block.

There was a time our blockchain used to have mining too, but it was abolished long ago even before Hive fork took place.

Only a very small percentage of produced Hive goes to block producers, Most go to content creators.