With road grime, eventually you reach an equilibrium where the new grime displaces the old grime.
This might be the place to put in a PSA for fenders and chainguard. Fenders help keep your bike cleaner in wet weather. Chainguard lets you use a heavier chain lube without it getting on your pants. I've been riding my all-weather bike in all weather for about 20 years, and it has shown minimal deterioration except for where the low quality chrome plating on some parts rusted. Oddly enough the Sturmey Archer hub leaks just enough oil to keep itself covered in a protective coating which also oils the chain. Clever design.
In my locale, summer storms are hard to predict, so it's a coin toss whether my bike will get wet on any given trip.