Well, it wasn't too scarce, absolutely, but it was too scarce practically, on the market. You had to rebalance stocks in the vaults and move it around with armored cars or ships, it was difficult to break into smaller denominations, you had to go dig some more up or refine it into monetizable units, etc., so lots of places that had a direct gold standard eventually moved to a gold-backed standard or added a silver/copper standard for smaller transactions. (Maybe a gold or fiat will be one of the subsat-tradeable currencies, for people who want to settle subsat credits. 🤷🏻‍♀️)

In the same way, you'd never run out of sats in the universe, but it may be that they become impractical for daily use, if Bitcoin rises in value too much and/or too many sats are taken out of commission, as you'd be needing to trade with increasingly smaller parts of a sat. That might already be the case, in some countries.