I think what GP means is that X amount of new bitcoins are "mined" every year, which is to say that X new bitcoins spring into existence from nowhere, so if the current exchange rate is Y dollars per bitcoin then XY dollars needs to flow into bitcoin per year for bitcoin to retain its current market capitalisation.

And I guess XY = $14 billion but I haven't bothered to look the numbers up.

I got 17bn, but with constantly changing prices a rough figure is fine.

Here's the previous day's block reward and current price. https://bitinfocharts.com/bitcoin/

The other thing about mining is the their costs are in hard currency, so there's not much opportunity to "hodl".

Those mined coins need to be sold once the electricity bill is due, so to maintain a stable price bitcoin needs an ongoing net dollar investment proportionate to the current price (taking halvings into account).