If there was no new flows the SF model cant be used, if you divide something by 0 it equals to "infinite". By the way I think that the value of gold will skyrocket to higher and higher prices over time.
It makes sense given the fact that no new gold can be created and we have a capped supply.
Interesting question my friend @vlemon.
Find here the article where he compares the srock 2 flow model for Bitcoin and Gold and Silver, it seems quite accurate.
https://medium.com/@100trillionUSD/bitcoin-stock-to-flow-cross-asset-model-50d260feed12