Although I’d point out that 4.8 W/kg puts you at the very pointy end of the TR bell-curve:
And similarly for the good ol’ Coggan power profile dataset, you’re in the “Excellent” bracket, and not too far off “Exceptional”.
So I wouldn’t be so quick to assume you’re not capable of more if you had the extra training time (and inclination) to hit 20 or even 30 hours per week.