Thermodynamic feasibility of the reaction alone cannot decide the rate of the reaction because for a reaction to occur it is important for the molecules to have an energy greater than the activation energy. So in order to increase the energy usually we increase the temperature so that the rate of the reaction becomes faster.

For example,

Diamond → Graphite ΔG=-ive

ΔG negative means that the reaction is feasible but this reaction is a slow process as energy is less than the activation energy.