The Almighty God has decreed:
“(The prescribed fast is for) a certain number of days. Whoever among you does not fast on those days because you are sick or on a journey, then (you should fast) the same number of days on other days. Those who are able to fast are also required to pay a fee (which is equivalent to the cost) of feeding a desperate person. Whoever volunteers to do more than good (which is paying more than bound to be paid), it is better for them. If only you knew how good it is for you to fast, you would (in spite of being sick or on journey).
Ramadan is the month when the Quran had been sent down, that Criterion which is a guide for people and which also includes the explanatory verses of that guide. So, whoever among you witnesses that month must spend it by fasting. Whoever is sick or on a journey may fast for the same number of days on other days.” (Al-Baqarah 2:184-185)
According to the verses above, everyone, other than the sick or the traveler, is obliged to fast during the days of Ramadan in the way God has prescribed. Fasting is recommended even to those who are sick or on a journey. Therefore, paying no amount of fee can compensate for the fast that is not performed deliberately on the days of Ramadan.
Besides, paying fidya is NOT a responsibility that should be fulfilled by those who do not fast, but it is prescribed to those who DO fast in Ramadan. This expression is clear in the verse 184. For details of this matter and the common mistake about the translation of this verse, please see the following article: