A growing money supply is a reaction to a growing economy. First the economy grows, then you increase the supply.
You can increase the supply beforehand, anticipating economic growth, but then you have to guess how much it'll grow and that can go wrong and you'll oversupply.
Central banks do a so-so job, inflation is a bit too high right now as we know. But compared to the epileptic wild swings of Bitcoin, USD is a steady rock.
My question about the Bitcoin economy was obviously purely rhetorical. There isn't any other than ransomware maybe. The inability to adjust Bitcoin supply means prices will always be instable compared to the fiat of most civilized countries and any attempt at running a business on Bitcoin will fail.