I believe it will all depend on how famous GRIN can get.
With the inflation being forever stable, we can't hope for the inflation to fall low enough to reach a level which can be supported by the community's interest level.
Inflation can be changed by developers as what we see from Stellar with their annoucement released recent days. Amazingly, let's look at Stellar price today. It has been pumped more than 10 percent temporarily. At its peak today, its price in realilty increased more than 13 percent.
Despite the unknown plan (or no plan at all) on inflation of Grincoin team, I think price is below 10k satoshis is very good to accumulate Grincoin.