Exactly right!
This calls for the inflation of the fiat currency.
When they will print more money then it will increase the supply of the fiat thus though the demand grows you will still have lot of supply. This way the circulation will keep on going in negative way. Thus it will do the demonetization of the currency.
Thats why they dont print more.
I believe that there is also factor that affects the value of currency like hold hoarding and gross domestic product. An example is japan, yen has a lesser value than a peso but as you can see japan is more successful compared to Philippines.