To some extent this statement is true of all engines. However in the case of later engines the compromises are fairly minor.
Consider the following for a typical jet transport mission:
Highest thrust required is at top of climb. Takeoff is usually reduced thrust if there is excess runway available.
Lowest SFC should be at cruise; as fuel is burned off, the thrust required is less, and the new optimum altitude is higher; thus thrust is reset to match the new cruise condition after step climb.
In descent, the engines are wasting fuel, so the lowest possible thrust and fuel use is desired.
ATC restrictions often mean you cannot fly an optimum climb/cruise/descend profile. BUT, All things considered, the modern turbofan covers these mission points pretty well.