I generally agree with your point, but I like the overall condition of my accessories to match the rifle where possible.
A brand new 1907 sling looks funny on a battered, worn 1903 Springfield rifle.
The scope is in excellent condition, just dirty. The dirt is likely from years of poor storage, rather than from battle. Not looking to restore it, just clean it.
Saddle Soap is your best option; otherwise used leather cleaner and polish for furniture or car interiors.